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HIGH DEFINITION TV 
THE LATEST NEWS 




$2.25 AUGUST 1987 

IN CANADA SZ.75 




LOGY - VIDEO - STEREO - COMPUTERS - SERVICE 



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GERNSBACK 



Listen to hidden signals 
on the FM band 



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of CE 

What it means 
to be a Certified 
Electronics Technician 



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For automated 
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A design primer 

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t Video News New Products 
Satellite TV Audio Update 



NOW GET SCOPE, COUNTER 

AND DMM INPUT ALL AT ONCE 

THROUGH ONE PROBE! 



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Gated frequency measurement. 

B sweep triggering during the 
intensified portion of the A sweep. 
Intensified portion frequency is 
measured with the counter/timer/ 
DMM. 



Delay time measurement. Delay 

time from the start of A sweep to 
the start of the B sweep is mea- 
sured with crystal accuracy. 



Channel 1 dc volts measure- 
ment. The average dc compo- 
nent of a waveform is measured 
directly through channel 1 with 
direct digital fluorescent readout. 



The Tek 2236 combines 
100 MHz, dual timebase 
scope capability with 
counter/timer/DMM 
functions integrated into 
its vertical, horizontal 
and trigger systems. For 
the same effort it takes to 
display a waveform you 
can obtain digital readout 
of frequency, period, 
width, totalized events, 
delay time and A-time to 
accuracies of 0.001%. 

The same probe is 
used to provide input for the 
CRT display and the digital 
measurement system, 
resulting in easy set-up. 
greater measurement confi- 
dence and reduced circuit 
loading. Probe tip volts can 
also be measured through 
theCh 1 input. 

Precision measurements 
at the touch of a button. 
Auto-ranging frequency, 
period, width and gated 
measurements are push- 
button-simple. And the 2236 
offers an independent float- 
ing 5000 count, auto-rang- 
ing multimeter with side 
inputs for DC voltage mea- 




B and width 



100 MHz 



No of Channels 



2 + Trig. View 



Max. Sweep Speed 5 ns/div 



Digital 

Readout 

Features 



Direct Ch 1 Voltage Meas. 0.5% DC; 2.0% 

AC RMS 
Resistance: .Otn to 200 Megfi 
Continuity/Temp: Audible/C or F° 
Totalizing Counter: — 1 counts to 8,000,000 
Direct Freq. Meas: 100 MHz to 0.001% ace. 
Period, Width Meas: 10 ns with 10 ps max. 

resolution 



Timing Meas. 
Accuracy 


.001% (delay and A-timewith readout) 


Trigger Modes 


P-P Auto, Norm. TV Field, TV Line, Single 
Sweep 


Weight 


7,3 kg (16.2 lb) 


Price 


$2650 


Wananty 


3-year including CRT (plus optional service 
plans to 5 years) 



surementsto0.1%. 
A built-in, auto-ranging 
a ohmmeter provides 
I resistance measurements 
from 0.01 H to 2Gfi— as 
well as audible continuity. 
Automatic diode/junction 
I detection and operator 
1 prompts serve to simplify 
1 set-up and enhance 
1 confidence in your 
1 measurements. 
J The 2236: scope, 
counter, timer, DMM 
plus a 3-year warranty 
—all for just $2,650. 
Contact your nearest dis- 
tributor or call Tek toll-free. 
Technical personnel on our 
direct-line will answer your 
questions and expedite 
delivery. Orders include 
probes, 30-day free trial and 
service worldwide. 

Call Tek direct: 

1-80O433-2323for 

video tape or literature, 

1-800-426-2200 for 

application assistance or 
ordering information. 

In Oregon, call collect: 
1-627-2200 



Tektronix 

COMMITTED TO EXCEULENCE 



Copyright e 1986, Tektronix, Inc. All righls reserved. TTA.797 



CIRCLE 92 ON FREE INFORMATION CARD 



Aug USt 1 98 7 Electronics 



Vol. 58 No. 8 




39 SCA RECEIVER 

Hear the hidden signals on the FM band. 
Rudolf Graf and William Sheets 

45 VERSATILE DIGITAL TIMER 

Precisely controls any AC-powered device in your home. 
Ross Ortman ____ 



57 RE ROBOT 

Part 9. Programming the robot. 
Steven E. Sarns 

75 PC SERVICE 

Direct-etch foil patterns for the digital timer. 




48 HIGH DEFINITION TV 

The first major change in television since the addition of color is on 

its way! 

Josef Bernard 

52 CERTIFICATION FOR ELECTRONICS TECHNICIANS 

The more you learn, the more you can earn. 
W. Clem Small, GET 



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55 TRANSISTOR AMPLIFIER DESIGN 

A basic design that solves many problems. 
Jack Cunkleman 



DHJ^y.'H.'Mih- 




6 VIDEO NEWS 

What's new in this fast- 
changing field. 
David Lachenbruch 

16 EQUIPMENT REPORTS 

Regency Informant Scanning 
Receiver 

26 COMMUNICATIONS 
CORNER 

Diversity reception and the 
wireless microphone. 
Herb Friedman 



28 SATELLITE TV 

HDTV standards. 
Bob Cooper, Jr, 

30 DESIGNER'S NOTEBOOK 

Logic family translation. 
Robert Grossblatt 

32 AUDIO UPDATE 

Expert answers. 
Larry Klein 



ComputerDicest 



IBM's NEW PS 2 

Brtol graphta, tvper speed 




DESIGN PC BOHRDS ON VOUft PC 

N«« ptOftoflH nwhfl it easy 



PAGE 61 







PAGE 48 



EKE 




100 Advertising and Sales 
Offices 

100 Advertising Index 
8 Ask RE 

101 Free Information Card 
12 Letters 

82 Market Center 
21 New Lit 
24 New Products 
4 What's News 



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The FM band abounds with hidden 
signals. Called SCA broadcasts or 
transmissions, some carry back- 
ground music for stores, offices, and 
restaurants; some carry data for per- 
sonal and commercial computer 
users; and some offer special inter- 
est programming for the handicap- 
ped and other groups. This month, 
we tell where those hidden signals 
are, and what makes them possible. 
Then we'll show you a receiver that 
will let you tune into the hidden world 
of FM radio. The story begins on 
page 39. 



■■iri.mj'.t.i.'yn 



THE SEPTEMBER ISSUE 

IS ON SALE 

AUGUST 4 

BUILD THE VIDEO PALETTE 

Add special color effects to a video signal. 



BUILD AN UNINTERRUPTIBLE POWER SUPPLY 

This 40-watt back-up supply kicks in at the first sign of trouble. 



CELLULAR TELEPHONE TECHNOLOGY 

Learn about the technology that's revolutionized mobile telephones. 

RE ROBOT 

Part 10 deals with robot applications. 

SCR/TRIAC COOKBOOK 

Practical SCR/Triac circuits for your next project. 



As a service to readers. RADIO- ELECTRONICS publishes available plans or information relating to newsworthy products. 
techniques and scientific and technological developments- Because of possible variances in the quality and condition of 
materials and workmanship used by readers. RADIO-ELECTRONICS disclaims any responsibility for trie safe and proper 

functioning of reader-built projects based upon or from plans or information published in this magazine. 

Since some of the equipment and circuitry described in RADIO-ELECTRONICS may relate to or be covered by U.S. patents, 
RADIO-ELECTRONICS disclaims any liability for the infringement of such patents by the making, using, or selling of any such 
equipment or circuitry, end suggests that anyone interested in such projects consult a patent attorney. 

RADIO ELECTRONICS, (ISSN 0033-7862) August 1987. Published monthly by Gemsback Publications. Inc., 500-B 
Bi. County Boulevard. Farmingdale, NV 11735 Second-Class Postage paid at Farmingdaie. NYand additional mailing offices, 
Second-Class mail registration No. g242 authorized at Toronto. Canada. One-year subscription rale U.S.A. and possessions 
$16.97. Canada $22-97. ell other countries S25.B7, All subscription orders payable in U.S-A, funds only, via international postal 
money order or check drawn on a U.S.A. bank. Single copies$2-25. r tge7 by Garnsback Publications, Inc. All rights reserved. 
Printed in USA 

POSTMASTER: Please send address changes to RADIO-ELECTRONICS. Subscription Dept Box 55115, Boulder. CO 
80321-5115. 

A stamped self- addressed envelope must accompany all submitted manuscripts and/or artwork or photographs if their return is 
desired should they be rejected. We disclaim any responsibility lor the loss or damage of manuscripts and/or artwork or 
photographs while in our possession or otherwise. 



Electronics 

Hugo Garnsback CI 884-1967) founder 
M, Harvey Gemsback. 
editor- in-chief, emeritus 



Larry Sleekier, EHF, GET. 
editor-in-chief 
and publisher 



EDITORIAL DEPARTMENT 
Art Kiel ma n, editorial director 
Brian C. Fenton, managing editor 
Cari Laron, WB2SLR, associate editor 
Jeffrey K. Holtzman, 

assistant technical editor 
Robert A. Young, assistant editor 
Julian S. Martin, editorial associate 
Byron G. Wets, editorial associate 
M. Harvey Gemsback, 

contributing editor 
Jack Darr, CET. service editor 
Robert F. Scott. 

se mi co nd u ctc-r ed Itor 
Herb Friedman, 

com m u n icati on s ed itor 
Bob Cooper, Jr. satellite-TV editor 
Robert Grossblatt, circuits editor 
Larry Klein, audio editor 
David Lachenbruch, 

contributing editor 

Richard D, Fitch, 

contributing editor 
Teri Senduto. editorial assistant 

PRODUCTION DEPARTMENT 
Ruby M. Yee, production director 
Robert A. W. Lowndes, 

editorial production 
Andre Duzant, technical illustrator 
Karen Tucker, advertising production 
Marcella Amoroso, production traffic 

CIRCULATION DEPARTMENT 
Jacqueline P. Cheese boro. 

circulation director 
Wendy Alanko, 

circulation analyst 

Theresa Lombardo, 

circulation assistant 

Typography by Mates Graphics 

Cover Foto by Bill Peterson, 
Design Color Labs 

Radio-Electronics is indexed in 
Applied Science & Technology Index 
and Headers Guide to Periodical Liter- 
attire. 

Microfilm & Microfiche editions are 
available- Contact circulation depart- 
ment for details. 

Advertising Sales Offices listed 
on page 100. 



m 




More Functions. Smaller Budget. 

Beckman Industrial Circuitmate" DMMs 

put hFE, Logic, Capacitance, Frequency and 

True RMS In Your Hand. For Less. 



Get more, for less. It's a simple defi- 
nition of value. For DMMs, value means 
finding the combination of capabilities that 
meets your needs at the right price Without 
losing sight of accuracy and reliability 
If you want more functions at a low price, 
Beckman Industrial's Circuitmate" 1 Digital 
Multimeters are the best value around. 

From the pocket-sized DM20L to the 
DM850, with true RMS capability and accu- 
racy to 0.05% ± 1 digit, Circuitmate DMMs 
give you the functions you need. 

For instance, the DM20L puts both a 
Logic Probe, a transistor gain function (hFE), 
arid a Hill range of DMM functions in die 
palm of your hand. For only 569-95. 

Then diere's the DM25L. Where else 
does SS995 buy you a Logic Probe, capaci- 
tance measurement, transistor gain function 
(hFE), and 24 DMM ranges including resist- 
ance to 2000 megohms? Nowhere else. 

When high accuracy counts, there's the 
DM800 with a 4 Vi digit display The DM800 



Is 

l:MI!nSDN 



irm 




DM20L Pocket-Size 
w/LogieS69.95* 

TTL Logic Probe: 20MHz 
Hi/lo/off indications 
Detects 25nS pulse 
widths 

iiFE(NPNorPNP): 
1 range (1000) 

DMM: Input Impedance— 
10 Megohms 
DCA/ACA-5 ranges 
(SfflVAtoMl 

Otlnts-8 ranges (200 ohms 
to 2000 Megohms) 

Continuity beeper 



also gives you frequency counting. A full- 
function DMM, and more, doesn't have to 
cost over £169.95, If it's a Circuitmate 
DM800. 

Or, for a few dollars more, get true RMS 
(AC coupled) to let you accurately measure 
non-sinusoidal AC waveforms, and all the 
capability of die DM800, in the DM850. 

Of course, there's a whole range of 
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DM2 5L 

Capacitance, Logic, 
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DM850 
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Data Hold display 
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Continuity beeper 



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DMB00 (Averagel 
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fits in a shirt pocket, yet gives you a full size 
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Beckman Industrial Circuitmate DMM. 




See your Beckman Industrial distribu- 
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For less. 

'Sug^sred lisl price (JUS) Willi batlery, test leads and manual. 



In-Service 
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CIRCLE 98 ON FREE INFORMATION CARD 



WHAT'S N EWS 



New instrument measures tape surface magnetism 



A new device that could lead to 
improved operation of many de- 
vices using magnetic tape has 
been developed by scientists at 
the Argon ne National Laboratory. 
The instrument, called a polar- 
ized-neutron reflectometer, uses 
neutrons to measure magnetic 
fields over microscopic depths at 
the surface of materials. 

"The instrument has already 
been used to measure the re- 
sponse of new recording materials 
to magnetic fields," says Cian 
Fletcher of Argonne. "Better infor- 



mation in this area could lead to 
improved magnetic recording 
technologies." 

"The trick," Fletcher said, "was 
to make the probe as sensitive as 
possible to magnetic fields at the 
surface. This was accomplished by 
sending the neutrons nearly paral- 
lel to the surface, so they graze it." 
The instrument can measure mag- 
netic fields within .0002-inch of the 
surface of the material. It can de- 
tect a magnetic field change over a 
distance as small as a billionth of 
an inch. 




GIAN P. FLETCHER, ARGONNE NATIONAL LABORATORY scientist, with the polarized-neutron 
reflectometer that could lead to improvements in magnetic recording. 



New infrared systems test 

gallium-arsenide wafers 

The National Bureau of Stan- 
dards reports two testing systems 
using polarized infrared light. 
They are expected to be especially 
useful in production control of 
gallium-arsenide (gAaS) wafers. 

GaAs applications are growing 
rapidly, but production of the 
near-perfect crystals needed for 
best performance is not as ad- 
vanced as with the older silicon 
technology. Detecting flaws in 
GaAs crystals should be easier 
with the new systems. One can 
scan an entire wafer; the other 
uses a 75- to 600- x microscope to 
view smaller portions. Both permit 
digital image storing and the use of 
false-color graphics to represent 
variations in characteristics that 
could point to potential problems. 

FCC abandons Consumer 
Radio Service 

The FCC reports that it "has de- 
clined to amend its rule to 
establish a Consumer Radio Ser- 
vice within the 462- and 467-MHz 
frequency segments now assigned 
to the General Mobile fiadio 
Service (CMRS)." That marks the 
end of an FCC-sponsored plan to 
replace the GMRS with a service 
that many felt would be of far-less 
value. 

Replies to a request for com- 
ments "failed to find any specific 
needs" for such a service, accord- 
ing to the FCC. Moreover, concern 
was expressed about the fate of 
present uses of the GMRS, includ- 
ing safety services provided by vol- 
unteer public service teams such 
as REACT (/fadio Emergency 
Associated Communications 
Teams). 

Consequently, the Commission 
concluded "that there was no rea- 
son to dislocate current GMRS 
users" and dropped the Consumer 
Radio Service concept. R-E 



Where's Your ELECTRONICS Career Headed? 




The Move You Make Today Can Shape Your Future 



Yes it's your move. Whether on a chess board 
or in your career, you should plan each move 
carefully. In electronics, you can move ahead 
faster and further with a 

B. S. DEGREE 

Put professional knowledge and a COLLEGE 
DEGREE in your electronics career. Earn your 
degree through independent study at home, 
with Grantham College of Engineering. No 
commuting to class. Study at your own pace, 
while continuing your present job. 

The accredited Grantham non-traditional 
degree program is intended for mature, fully 
employed workers who want to upgrade their 
careers . . . and who can successfully study 
electronics and supporting subjects through 

INDEPENDENT STUDY, AT HOME 

Free Details Available from; 

Grantham College of Engineering 

10570 Humbolt Street 

Los Alamitos, California 90720 



Independent Home Study Can Prepare You 

Study materials, carefully written by the Gran- 
tham staff for independent study at home, are 
supplied by the College, and your technical 
questions related to those materials and the 
lesson tests are promptly answered by the Gran- 
tham teaching staff. 

Recognition and Quality Assurance 

Grantham College of Engineering is accredited 
by the Accrediting Commission of the National 
Home Study Council. 

• 

All lessons and other study materials, as well as com- 
munications between the college and students, are in the 
English language. However, we have students in many 
foreign countries; about 80% of our students live in the 
United States of America. 

i 1 

Grantham College of Engineering 
10570 Humbolt Street, Los Alamitos, CA 90720 

Pleose mail me your free catalog which explains your 
B.S. Degree independent-study program. 



Name. 



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Video 
News 



DAVID LACHEETBRUCH, 

CONTRIBUTING EDITOR 



• TV Sets Large and. Small. TV sets with giant 
cathode- ray tubes are now included in many 
manufactures' lines; at the other end of the 
spectrum are the first active-matrix LCD color 
sets. Active-matrix LCDs produce a picture that is 
vastly superior in terms of resolution and color 
to the passive-matrix type used in the LCD sets 
introduced to date. 

Panasonic originally showed a sample of its 3- 
inch "Pocket Watch" LCD TV set almost a year 
ago, then shelved it because of manufacturing 
problems. Now it has been introduced in a 
somewhat different form— including stereo -FM/ 
AM radio (with headphones). Because of the 
inherent expense of producing the active-matrix 
LCD's, as well as the high value of the Japanese 
Yen m relation to the Dollar, Panasonic has put a 
list price of $550 on that little TV set. In addition, 
Toshiba plans to offer a 4-inch active-matrix LCD 
TV this 6ul, and has said it is "aiming" at a price 
of around $400. 

On the large screen front, several manufac- 
turers are introducing sets with screens larger 
than 26 or 27 Inches, but smaller than the 35- 
inch size produced initially by Mitsubishi, and 
later adopted by Sanyo, Sharp, Fisher, and Sears. 

Panasonic, in its new line, is featuring a 31- 
inch set, as is North American Philips, which 
manufactures sets under the Magnavox, Philco, 
and Sylvania brands, Now Toshiba, the originator 
of the FST (Flat, Square Tube), has introduced its 
FST Magnum, a tube that measures 30 inches, 
diagonally, and whose face is virtually flat. The 
rest of the industry is choosing up sides among 
the various sizes. Whichever they choose, the new 
types are luxuries indeed, with prices ranging 
from $2,000 and up. 

• Super Camcorder. The first combination 
camera-recorder capable of making home movies 
with higher resolution than broadcast TV or 
videodisc has been announced by Hitachi. Hitachi 
says it has developed an MOS camera pickup that 
can produce 450 lines of horizontal resolution, 
which it plans to mass-produce starting this 
summer. Until Hitachi's development became 
known, it was believed that camera pickups 




matching the resolution capability of the new 
Super-VHS system (Radio-Electronics, May, 
1987 ) would be unavailable at a consumer price. 
Hitachi now says it will deliver a high-resolution 
Super-VHS camcorder this fall. RCA, whose VCR's 
and cameras are made by Hitachi, is expected to 
come out with a similar version. 



• Menu-Driven TV Sets.Television manufac- 
turers are borrowing from computers in 
providing what they see as the very latest in 
tuning convenience—the on-screen menu. That 
feature is carried to the furthest extreme in the 
new RCA and Magnavox lines, in which virtually 
every TV function may be tuned with on-screen 
indicators and legends. In RGA's Dimensia audio- 
video line even the FM- and AM -radio tuning is 
done on the TV screen, A typical TV tuning 
system gives on-screen indication of such 
functions as mono, stereo, SAP (for Second Audio 
Program), bass, treble, balance, input, brightness, 
picture, color, tint, sharpness, cable or broadcast 
tuning, on-off time setting, channel blockout (for 
parental control), and so forth. The Magnavox 
Total Remote Control system even has a novel 
"channel captioning" system. The user can 
identify each channel by its call letters or 
broadcast- or cable-network (HBO, CNN, etc.) 
affiliation, and airy tune that channel is displayed, 
the identification also is flashed on the screen. 

Double-Tuner TV sets. Another innovation in 
the new models is the two-tuner TV set. The first 
digital TV models, you'll recall, had the picture-in- 
picture feature that superimposes a second 
picture in a corner of the screen, but required a 
second picture source, such as a VCR, to use the 
feature. New color-TV sets from Sony and Hitachi 
get around that by incorporating two tuners. That 
allows the viewer to watch any two channels 
simultaneously, switch them around, halt one to a 
still picture, and so forth. Interestingly, the new 
double-tuner picture-in-picture storage system is 
digital, but other processing circuits are analog. 
And therein lies another trend in the new 
models: Use digital technology where necessary 
to provide a special feature; otherwise stay with 
tried-and-true analog circuitry. R-E 



TEST EQUIPMENT THAT MEASURES UP TO YOUR 
mr SPECIFICATIONS 






DMM-300 $79.95 

3,5 DIGIT DMM / MULTITESTER 

Our besl model, A highly accurate, hi 
tion DMM loaded with many exrr .7 features 
Audible continuity, capacitance, transistor 
lorn pom lure at id conductance oil in one Hand - 
hold malar. Temperature probe, tost leads and 
battery included 

» Basic DC accuracy, plus or minus 0.26% 
« DC voitaqe 20Omv - 1000v. B ranges 

■ AC voltage 200mv - 760v. 5 ranges 

• Resistance; 200 ohms — 2QM ohms. 
S ranges 

» AC/DC currant: 200uA — 10A„ G ranges 
- Capacitance: 200Qpf — 20ul 3 ranges 

* Transistor taster: hFE tost, NPN, PNP 

• Temperature taster 0° — ZDOO 4 F 

■ Conductance 200ns 

* Fully over-load 1 protected 

■ Input impedance. 10M ohm 




DMM-200 $40.95 

3.5 DIGIT PULL FUNCTION DMM 

H*Qfo accuracy. 20 amp currant capability and 
many range sotting* make this model ideal for 
serious bench or fiftid wort Tilt stand lor 
tinnds-fTW upetaftun 2000 how u. 
with standard 9v Mil Probes and battery 
included 

- Buic DC accuracy: plus or minus 

• DC voltage 200mv - lOOOv, & rangas 

- AC voltage. 200rctv - 750v. b ranges 

• Resonance 200 ohms - 20M ohms. 
G ranges 

■ AC DC current; 200uA - 20A. 6 ranges 

• Fully ovDf-loail protected 

• Input impedance: TOM ohm 

• 160 x 86 m 37mm. we+ghs 320 grams 



:jJ!Jt>H WJSTUUMENrs dmmtoo 



DMM-700 $49.95 DMM- 100 $29.95 

3 5 DIGIT AUTORANGING DMM 3.5 DIGIT POCKET SIZE DMM 



Autornnge convenience or hilly manual oper- 
ation ScJoclBbUi LO OHM modo permits 
accurate >n cJffiuil resistance measurements 
involving tami conductor |uru;imns MEM 
mode for measurements relative to a specific 
reading Probe* and battery included. 

• Basic DC accuracy plus *>' minus 5% 

» DC voltage 20Qmv - lOOOv. autoranging 
or B manual ranges 

• AC voltage 2v — 7SOv outoran^wHi 

or 4 manual ranges 

• Resistance: 200 ohms - 20M ohm* 
autoranging 

- AC DC ciirrmii 20mA — 10 A. 2 ranges 

- Fully over-load ptotiDctud 

• Audible continuity taster 

• Inpcrf impedance: 10M ohm 

• 150 x 7& x 34mm. vvntghi 230 grams 



Shtnpocket portability with no compromise 
in features or accuracy- Large, easy to read 
6" LCD display. 2000 hour battery Ida with 
standard Shy cofi provides over two yoars or" 
average use Probes and battery included. 

• Basic DC accuracy' plus or minus 0-6^ 

• DC voltage: 2v — lOOOv, 4 ranges 

• AC vottage: 200v — 75 0v. 2 ranges 

• Resistance: 2k ohm a - 2M ohms. 4 ranges 

• DC cunont 2mA — 2A. 4 ranges 

> iTvar-lood pr otectod 

• Input impedance- 1QM ohm 

• 1 30 k 75 x 2flmm. weighs 135 grams 



MODEL 2000 $349.95 

20 MHz DUAL TRACE OSCILLOSCOPE 

Model 2000 combine* useful features and 
quality. Frequency calculation and phase measure 
mont are quick find easy in the X-Y Mode S^rvico 
technicians will appreciate the TV Sync circuitry to* 
viewing TV -V and TV-H as writ as accurate synchro™ 
uiton'of the Video Signal. Blanking Pedestals. VlTS 
and VerticEe' Horizontal sync pulses 

■ Lab quality compensated 10X probes included 

* Built-in component tester 

* 110/220 Volt operation 

- X-Y operation * Bright 5" CRT * TV Sync filter 



MODEL 3500 $499.95 

35 MHz DUAL TRACE OSCILLOSCOPE 

Wide bandwidth and exceptional 1 mvYDIV sensitivity 
make the Model 3500 a paworful diagnostic tool for 
engineers or technicians. Delayud triggering allows any 
portion of a waveform to be isolated and expanded for 
closer inspection Variable Holdcff makes possible the 
stable viewing of complex waveforms. 

■ Lab quality compensated 10X probes included 

■ Delayed and single sweep modes 

• Z Axis intensify modulation 

• X-Y operation » Bright &" CRT » TV Sync |,| m 



0PM- 1000 



$54.95 



3.5 DIGIT PROBE TYPE DMM 

Autoranging, pert style design for the ultimate in portability and 
ease of use. Custom BO pin LSI chip increases reliability. Audible 
continurty tester and data hold feature for added convenience. 
Case, test leads and batteries included 

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conduction period (angle) 
through each half-cycle of line 
voltage applied to the Triac (TR1), 
which is connected in series with 
the load across the AC powerline. 
The conduction period is varied 
and controlled by the unijunction 



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transistor (Q3) circuit: a relaxation 
oscillator that is coupled to Triac 
TRVs gate through pulse trans- 
former T1. The oscillator's basic 
frequency depends on R7/C4. 

The bridge rectifier develops ap- 
proximately 165 volts peak, which 
is regulated to approximately 13.5 
volts by silicon rectifiers D5 and D6 
which are in series with 12-volt 
Zener diode D8. 

Also connected across the 13.5- 
volt source is Q3's RC timing net- 
work, R3/C2. For proper circuit op- 
eration, R3 must be adjusted so 
the voltage across C2 just rises to 
the conduction point of Q3 at the 
end of each half-cycle of the line 
voltage. Under that condition, Q3 
delivers a current pulse through T1 
to TRTs gate as the instantaneous 
line voltage drops close to zero. 
Since the line voltage is near zero, 
no appreciable current flows 
through the load (connected to 
SOI) when the Triac conducts. 

The adjustable dimming control 
R2, is a 10Kwi rewound potentiom- 
eter. The voltage tapped off R2 
feeds an RC timing network con- 
sisting of R3 and rate control R4 in 
series with C3, a 100-|iF, 16-volt 
electrolytic capacitor. The voltage 
across C3 is applied to the base of a 
Darlington amplifier (Q1 and Q2) 
that uses 2N3565 or similar NPN 
silicon transistors. The Darling- 
ton's emitter output is connected 
to timing capacitor C4 and to the 
emitter of Q3. 

As C3 charges, its voltage is ap- 
plied as a "bootstrap" voltage to 
C4. Since the Triac is normally off, 
or nearly so, we simply cause it to 
turn on earlier and earlier in each 
half-cycle of the supply voltage 
when we want to increase current 
through the load that is connected 
to socket SOL On the other hand, 



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to reduce current through the load 
we dim control R2 to reduce the 
voltage across C3. That lowers the 
"bootstrap" voltage available for 
C4 so Q3 and TR1 begin con- 
ducting later and later in each half- 
cycle of the line voltage. 

When rate control R4 is 500K, 
the maximum fade-up and fade- 



down time is about 1 minute. 
Changing R4 to S megohms in- 
creases the control range to about 
15 minutes. 

Pulse transformer T1 is wound 
on a 1-inch length of 3 /s-inch diam- 
eter ferrite rod. Each winding con- 
sists of 100 closewound turns of 
No. 36-40 enameled wire. 



Inductor L1 is a hash suppresser 
made of 50 closewound turns of 
No. 18 enameled wire on a 2-V-- 
inch piece of the same type of rod 
as used for the core of T1, Insulate 
the coil with plastic tape. 

Resistor R7 may have to be ad- 
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Letters 






LETTERS 

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soo-a £/■ couNry souls, vard 

FARMINGDALE, A!Y //7-3S 



LEADER DMM/STORAGE 
OSCILLOSCOPE 

I was pleased to see Leader's 
model LCD-100 DMM/Storage Os- 
cilloscope (see Fig. 1) featured in a 
Radio-Electronics "Equipment Re- 
port" (June, 1987). While the re- 
view was informative, the pricing 
information was incorrect. The ac- 
tual price is $850.00, and the unit is 
currently available. 
MARC REINER 
Leader instruments Corp. 
380 Oser Ave. 
Hauppauge, NY 11788 




ON SOLDERING 

I enjoyed the article, "Solder- 
ing: Old Techniques and New 



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Technology," by Vaughan D. Mar- 
tin, in the May 1987 issue of Radio- 
Electronics. There should be more 
articles such as that, which give 
good data to the inexperienced. 
How else will they be able to 
learn? 

1 would like to add two points: 
One is that we never use any sol- 
dering iron that isn't temperature- 
controlled for electronics solder- 
ing. The old "wood-burning" tools 
are history, but I didn't see any 
mention of temperature-con- 
trolled irons; they really aren't that 
expensive and are essential to 
good soldering. 

The second point is on tech- 
nique: The iron must always have 
an excess of solder in order for the 
heat to transfer quickly. Get on 
and get off the joint; otherwise, 
the heat will travel away from the 
joint and heat other areas. Under- 
standing heat flow, of course, is 
what soldering, brazing, and weld- 
ing are all about. A good rule of 
thumb would be to apply solder to 
the tip and joint simultaneously — 
making contact between the tip 
and the solder is very important. 

Keep up the good work. 
GERALD F. DULIN 
Torrance, CA 

ON PATENT APPLICATIONS 

I would like to thank David 
Pressman for his remarks con- 
cerning my article on patents, 
which appeared in the January, 
1987 issue of Radio-Electronics. His 
corrections to details contained 
within the text illustrate the need 
for continuous monitoring of pat- 
ent requirements, and the wisdom 
of paying an attorney or an agent 
to at least review the application. 

1 agree that the task of applying 
for a patent is not simple, and that 



12 




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the expression "relatively simple 
task" (the editor's words, inciden- 
tally) could mislead the reader. 
However, I think that the intent 
was to introduce the concept that 
applying for a patent is a finite task 
comprised of established pro- 
cedures, standard form, and a 
structured method of describing 
the invention. 

As to Mr. Arnold's letter con- 
cerning the water alarm: Back in 
1975, I invented a wetness alarm 
that used the SCR circuit, and 



packaged the alarm in a plastic 
sandwich box. The alarm worked 
quite well, even after sitting under 
a hot-water heater for more than a 
year. In consideration of patenting 
the idea, I searched the archives of 
the Patent and Trademark Office 
and found numerous patents hav- 
ing to do with sensing water and 
actuating switches. 

In addition, I collected advertis- 
ing for a number of commercial 
enterprises marketing both water 
alarms and wetness-detection sys- 



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terns for industrial use. Although I 
did not come across a water alarm 
that used the SCR circuit, 1 con- 
cluded that a patent for a water 
alarm would not be profitable. I 
used the circuit as an example in 
the patenting article because it sat- 
isfied the need for a simple, easy- 
to-describe circuit, and yet one 
that exhibited a unique quality. 
DAVE SWEENEY 

TESTING SEMICONDUCTORS 

I was just reading "Testing Semi- 
conductors" in the April 1987 issue 
of Radio-Electronics. I enjoy read- 
ing your articles, because they re- 
fresh my memory on how various 
components work. 

In the article, you printed an er- 
ror that is very common in the 
field. In Fig. 1, you are measuring 
the reverse current of a diode 
using a microammeter (the text 
says milliameter). The reverse cur- 
rent through the diode should be 
extremely small as compared to 
the current used by the voltmeter 
(M2). With some voltmeters, that 
current is much higher than with 
others. It is a good practice, when 
measuring the properties of any 
device, to eliminate any external 
interference that you can. In the 
present case, simply placing the 
voltmeter before the current 
meter would quickly eliminate the 
problem. 

I find that many measurements 
in the field are inaccurate, due to 
the technicians involved not 
knowing how the test equipment 
affects the circuit that it's being 
connected to. I once witnessed a 
technician connecting a meter 
with a 600-ohm impedance to the 
input of a transmitter. That was 
done to measure the audio signal 
going into the transmitter. 
However, the meter was con- 
nected in parallel to the input, 
producing a 300-ohm impedance; 
therefore, the signal level was off 
by enough to indicate a problem 
with the transmitter, when, in fact, 
there was no problem — just an in- 
accurate measurement. 
RICHARD P. MORLEY 
APO, NY 

PC CLONE 
Thanks, Radio-Electronics: You 

finally printed an article, "IBM- 
continued on page 22 



DESCRAMBLER ARTICLE PARTS 



February 1984 Issue 

We stock the parts, PC Board and AC 
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descrambler appearing in Radio-Electronics. 

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February 1987 Issue 

We stock the parts, PC Board and AC 
Adaptor for an article on a tri-mode cable TV 
desc ram bier appearing in Radio-Electronics. 

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Original (14 to 18 volt DC @ 200 ma} AC 
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Includes (1 ) Plessey SY323 Saw Filter plus 
(1) Toko E520HN-300023 Coil. 



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Thanks to what Regency calls 
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about one quarter of that. 




CIRCLE 37 ON FREE INFORMATION CARD 



Using the Informant 

How easy is it to use the 
Informant? With only two knobs 
and three toggle switches on the 
front panel, you know it can't be 
too difficult. One of the knobs, of 
course, is the volume control, 
which also serves as the power 
switch. The other is the squelch 
control. 

The hold switch is used to lock 
the scanner on a single frequency 
of interest. Pressing it once puts 
the scanner in the hold mode; 
pressing it a second time causes 
scanning to resume. The hiway/ 
city switch is used to select either 
state- police frequencies (hiway) or 
local city- and county-police fre- 
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other position is used to select the 
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Rounding out thefrontpanelisa 
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the type of signal (state, local, or 
weather) being monitored, and 
the scanner's mode. 

The Informant covers state, city, 
and county police frequencies 
from 36-47 MHz (VHF Low), 



16 




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Training From NRI! 



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In our catalog you'll find over 450 
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CIRCLE 86 ON FREE INFORMATION CARD 



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150-163 MHz (VHF High), and 
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inches) and it comes equipped 
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Also included are a DC power cord 
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for temporary installation. 

The Informant's simplicity is 
sure to be a great attraction to peo- 
ple who are unfamiliar with scan- 
ners, and to those who want an 
easy-to-use scanner for mobile 
use. But simplicity has its disad- 
vantages, too. Regency chose not 
to include a delay switch on the 
INF-1, probably to keep it looking 
as clean and simple as possible. 
Without a delay switch, the user 
has no control over how long the 
scanner will wait on a single fre- 
quency for the response to a trans- 
mission. The Informant waits less 
than a second, and in many cases 
that's just not long enough. 

The only other thing missing is a 
frequency display. In a sense, it's 
really not needed, but it would be 
nice to have some way to identify a 
given channel. 

Even though a lockout switch is 
not included, it is possible (by 
using two of the toggle switches in 
combination) to force the scanner 
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The Informant INF-1 sells for 
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TurboScan technology and simple 
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CIRCLE 38 ON FREE INFORMATION CARD 

CONSUMERS'S GUIDE TO PRI- 
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CIRCLE 39 ON FREE INFORMATION CARD 

INTRODUCTION TO PACKET RA- 
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What equipment do I need? How 
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booklet also includes FCC licens- 
ing information. It is available 
upon request from Kantronics, 
1202 E. 23rd St., Lawrence, KS 
66046. R-E 

CIRCLE 40 ON FREE INFORMATION CARD 



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LETTERS 



continued from page 14 



Compatible Clone Computer," 
(February I987 Computer Digest) 
that I can use and relate to. That 
one article, to me, is worth the 
three years or so that I have been 
carrying a subscription. I want to 
have a computer soon, and I think 
the article was my ticket to getting 
one. 
That is not to say that I have 



found the electronics articles 
useless. I subscribe to your maga- 
zine because I want to learn more 
and understand what's going on. 
I'm a mechanical-engineering stu- 
dent. My only connection to elec- 
tronics was a sorry two years that I 
spent learning printed-circuit art- 
work preparation from the ground 
up. You know — the "make a mis- 
take and we'll tell you what you did 
wrong" approach. I made a lot of 
mistakes. 
Anyone who's taped a PC art- 



Hands-on 





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tJ\om 



■ IF YOU'RE THE KIND OF READER that 
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copy ot Hands-on Electronics now. Hands-on 
Electronics is crammed futl of electronic proj- 
ects that you won't be able to wait to build lor 
yourself. You can expect top-notch digital proj- 
ects, fun-to-play electronic games, valuable 
add-on computer projects, BCB and shortwave 
receivers, photographic dark room gadgets, de- 
vices to improve your car's performance, test 
equipment ideas, and more in every issue of 
Hands-on Electronics. 



■ YOU CAN HAVE THE NEXT TWELVE IS- 
SUES of Hands-on Electronics delivered to 
your home for only $18.95 — saving $11.05 off 
the single copy price. 



■ EVERY ISSUE OF Hands-on Electronics 
will continue to contain a variety of construction 
articles to suit every taste. In addition, feature 
articles on electronics fundamentals, test equip- 
ment and tools will round out each issue. Of 
course. Hands-on Electronics will continue to 
provide new product and literature listings to 
keep you up to date on the latest developments 
in electronic technology. 

■ GET IN ON THE ACTION! Order your next 
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check or money order — no cashl 



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Detach and mail today 
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HANDS-ON 
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SUBSCRIPTION DEPT. 
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MOUNT MORRIS, IL 
61054 

ARE87 



work, made the manufacturing 
drawing for the boardhouse, and 
drawn the component layout 
wants to get a more concrete feel- 
ing for electronics. Well, the next 
step is to stuff boards, get to know 
actual components, learn how to 
solder, etc. And then get into the 
theory as a final step. 

Radio-Electronics is giving me a 
library on those things, the "how 
to," and the advertisers for the 
parts and the tools. 

Again, thanks! And I also think 
that putting the magazine in a 
mailing wrapper is great — no more 
mangled covers. 
CURTIS E. VAILLETTE 
Madison, Wl 



ADDITIONAL INFORMATION 

In response to the question 
about operating 117-volt, 60-Hz 
equipment on 220-volt, SO Hz 
power lines that appeared in "Ask 
R-E" in Radio-Electronics, May 1987, 
here's some additional informa- 
tion. I was stationed overseas for 
four years; and as the staff Elec- 
tronics Officer, I did a lot of modi- 
fications of that type. 

Most manufacturers have kits 
that you can buy that compensate 
for the slower rotation speed of 60- 
Hz motors when operated on 50- 
Hz power. A different-size drive 
wheel is usually available for most 
turntables and tape recorders. A 
different-size pulley is usually 
available for motors that drive 
washers and dryers. 

Clock and timer modifications 
are available for 50 Hz, but are 
hardly worth the trouble. Buy a 
clock in the country where it' to be 
used. The timers on your washer, 
dryer, oven, etc. will run a little 
slower, but they can be set to com- 
pensate for that. 

The resistive load of oven, stove, 
iron, toaster, room-heater, and 
clothes-dryer heating elements 
will work well on either 60 or 50 
Hz. Of course, the voltage must be 
correct. In a clothes dryer, you can 
modify the circuit to include a 
transformer on the drive motor 
and timer circuit. That will greatly 
reduce the size of the transformer 
that is needed. 

Forget about operating a TV set 
built for US video systems and 60 
Hz: Rentorbuy one in the country 



22 



that you're in; modifications are 
too complicated to get into. 

Do not buy transformers in the 
U.S. to take overseas with you. 
There are always people being 
transferred back to the States or 
elsewhere, and who want to get 
rid of the transformers that they 
have. You can save a bundle. Even 
if you buy new ones, buy those 
wound to operate on 50 Hz; they 
have more iron in them and will 
operate cooler for a given load. 

Some people have one large 
transformer for the whole house; 
others have them for individual 
appliances. Whichever way you 
go, watch the load. Add up all the 
possible loads that you will have 
and get a transformer that's big 
enough to handle the job. 

If you buy equipment overseas, 
be sure that the adapters are avail- 
able to operate it when you get 
back to the U.S. 

Whatever you do for yourself or 
for somebody else, if you modify 
the equipment or change the wir- 
ing, be sure to document what you 
have done and what it was like be- 
fore you started. That will be a 
great help at some later date, for 
whomever tries to change it back 
once again. 

I've read your publications since 
1 was age 12, and that was 60 years 
ago; I've been a subscriber for at 
least 30 years. 
ROY A. NORMAN 
Lcdr. U5N Ret. 
Brunswick, GA 



HEADLAMP WARNING 

On page 67 of the April 1987 is- 
sue of Radio-Etectranics a circuit is 
shown that warns of the head- 
lamps of a car being left on. If the 
voltage from the fuse panel used 
to power the piezobuzzer and LED 
is taken after the dimmer control 
for the panel lights, it is possible 
that there may not be enough volt- 
age to drive those components. 

When I built my own version of a 
warning circuit a few years ago, I 
used power from the parking 
lamps, which are not dimmed. 
Though it is unlikely that the car's 
fuse block will come after the dim- 
mer control, if that is the case, my 
solution is bound to work well. 
KEVIN STEBLETON 
Royal Oak, Ml R-E 



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Products 



STATIC CONTROL, Screen Prep 
consists of two individual, dis- 
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Screen Prep also provides a con- 
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The stripper uses two parallel- 
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The model C strips any size 
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02165. 

ODOMETER DATA COMPUTER, 

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A simple hookup and command 
to the printer produces a printed 
record that can be submitted to 
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The compact computer, which is 
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dash due to temperature ex- 
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Communications 
Corner 

Diversity microphone transmission 




WE HAVE DEVOTED SEVERAL COLUMNS 

in the past to the subject of diver- 
sity reception as il pertains to 
high-frequency shortwave signals 
(to 30 MHz); those signals are par- 
ticularly sensitive to variations in 
polarization. Although we call the 
effects of polarization "selective 
fading," in fact the signal might 
not vary in strength at all; only its 
polarity varies. However, the typ- 
ical receiver sees a change in po- 
larization as being a change in 
signal strength. 



In the usual form of diversity re- 
ception, a special receiver switch- 
es between horizontal and vertical 
antennas, always selecting the an- 
tenna input that provides the max- 
imum signal strength. Naturally, a 
broad range of signal level is ac- 
cepted as "satisfactory" to prevent 
the antennas from switching back 
and forth continuously. 

But signal polarization isn't the 
only reception problem that re- 
quires diversity reception, nor 
does diversity reception neces- 



sarily require vertical and horizon- 
tal receiving antennas. In par- 
ticular, FM wireless microphones 
can be seriously affected by signal- 
phasing problems caused by mul- 
tipath reception. Although the 
problem can usually be resolved 
through diversity reception, the 
two antennas involved are both 
vertically polarized. 

For those of you unfamiliar with 
the wireless microphone, it is ac- 
tually a system consisting of a 
transmitter and a receiver. The 



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transmitter might be combined 
with the microphone into a micro- 
phone-shaped device, or the 
transmitter might be independent 
of the mike so it can be worn on a 
belt or concealed under the user's 




HV 



WIRELESS 
MICROPKPGNE 



WIRELESS 
RECEIVER 



FIG. 1 



V. 




g 

REMOTE 
ANTENNA 



180° 

DELAY 



RECEIVER 



ELECTRONIC 
SWITCH 



I I 



FIG. 2 

clothes. Wireless mikes are used 
by those who prefer to roam unen- 
cumbered by the umbilical cord of 
a conventional microphone. Also, 
wireless sensors, which are usu- 
ally wireless-microphone based, 
are now built into electric instru- 
ments such as guitars so that per- 
formers can also dispense with the 
umbilical cord between instru- 
ment and amplifier. 

In principle, the wireless mikes 
are much like the inexpensive FM 
microphone kits you can buy from 
electronics hobby stores for a few 
dollars; those, of course, broad- 
cast a signal that can be received 
by a conventional FM radio. Pro- 
fessional wireless microphones, 
however, usually pack much more 
power, have a wider frequency re- 
sponse for high fidelity, and oper- 
ate on VHF frequencies specifical- 
ly assigned for stage, radio, and TV 
communications. 

Because they operate on VHF 

frequencies, they are prone to 

multipath reflections from by steel 

continued on page 31 



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Satellite TV 



Is HDTV the key to an international standard? 




BOB COOPER, JR., 

SATELLLITE TV EDITOR 



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IN OUR LAST COLUMN WE DISCUSSED A 

plan to gradually phase out the 
525-line NTSC national television 
standard. Its replacement would 
be a new wideband, High 
Definition TV (HDTV) system hav- 
ing more than 1,000 scanning 
lines. What makes the wideband 
plan feasible is the concept of sat- 
ellite distribution of television 
programming, which, perhaps, 
will ultimately replace terrestrial 
VHF and UHF transmitters. 



The most logical way to produce 
high-definition video is to double 
the picture bandwidth. If a 6-MHz 
bandwidth is required for 525-line 
NTSC video, a 12-MHz bandwidth 
will certainly accommodate 1,125- 
line video. But it's impossible to 
allow all existing television sta- 
tions to increase their bandwidth 
within the existing VHF and UHF 
television spectrum because the 
spectrum is essentially filled to ca- 
pacity already. Also, the FCC has 



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MEMPHIS, T3EHK1SSEE 

1987 National Professional 
Electronics Convention 

NESDA [Inc. NATESA). I5C6T £ TESDA ON THE MISSISSIPPI RIVER 



The Peabody • Memphis, TN 
August 1Q-' 

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1-15, 1987 W 

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FIG. 1 



been chipping away at both the 
top end (channels 70-82) and the 
bottom end (channels 14-20) of the 
UHF band for more than a decade, 
siphoning off UHF channels for 
two-way radio and other uses. 

Out of spectrum 

Spectrum space is, in fact, al- 
most non-existent until the micro- 
wave region near 12 GHz. There, 
perhaps with careful planning, is 
the means whereby we can fit in 
the wide bandwidths required for 
HDTV. CBS would like to see ter- 



28 



INTERESTED IN SCRAMBLING? 

Bob Cooper's CSD Magazine 
maintains a 24 hour per day Scramble- 
Fax-Hotline telephone service (305/771- 
0575) which you may cat! to obtain a 3- 
minute recorded update on the latest hap- 
penings in the satellite scrambling world, 
Scramble- Fax Newsletter is also pub- 
lished to keep you abreast of the latest 
events in descrambltng, including sources 
for descrambling chips and equipment. 
For information, write Scramble Fax, P.O. 
Box 100858. Ft. Lauderdale, FL. 33310 or 
telephone 305-771-0505. 

If you have a dish of your own, tune in 
the Caribbean Super Station (Western 5, 
transponder 23) Tuesdays at 7 PM east- 
ern for a special weekly Bob Cooper re- 
port. Also tune-in Boresight at 9 PM 
Thursday nights (Spacenet 1, transpon- 
der 9) for a weekly one- hour report on the 
activities in the home TVRO field. 



restrial delivery of HDTV signals, 
meaning that the signals originate 
from a microwave transmitting an- 
tenna mounted on a tall tower or a 
tall building. Virtually nobody else 
likes that concept because trans- 
mission ranges would be short 
(typically, only direct line of 



sight — under 25 miles). Most favor 
a satellite-to-home approach, 
using the DBS-assigned 500-MHz 
bandwidth between 12.2 and 12.7 
GHz. A few engineers are looking 
at the next higher satellite band, 
Ka, in the 20-CHz region, because 
precise beam shaping would allow 
footprint-patterned satellite trans- 
mitting antennas to cover irregular 
shapes (such as the state of New 
Jersey) with great accuracy. 

It's assumed that the U.S. will 
make the decision to implement 
HDTV before 1990 because that's 
the year that the Japanese expect 
to launch a fully operational three- 
channel HDTV satellite (in the 12 
GHz-band). Already, new satellite 
receivers, television monitors, 
and videotape decks have been 
designed to support their HDTV 
program. When the Japanese inau- 
gurate the HDTV service they plan 
to have all of the consumer receiv- 
ing equipment on store shelves 
ready for delivery. 

The revolution at the receiving 
end, while spectacular, is hardly 
the full effort. To produce HDTV 



broadcasts, entirely new studio 
and transmission equipment and 
programming had to be created, 
because in addition to the en- 
hanced resolution, the aspect 
ratio (width to height) was 
changed as well : from 4 x 3 to 5 x 
3. (Sony began delivering 5x3 
HDTV cameras and professional 
tape decks late in 1986, and new 
production studios using that 
equipment are already operating 
in several US cities.) 

Back-door standards 

Although HDTV addresses itself 
to a better-quality picture, in actu- 
al fact it is interlocked with the 
concept of a global TV standard, 
and for many communications 
people the idea of a global TV stan- 
dard is more important than 
whether the TV screen can show 
greater picture detail. But the idea 
of a high-resolution picture has 
more sizzle and snap than tech- 
nical standards — about which the 
average user couldn't care two 
hoots — so we will most probably 
continued on page 74 




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ADDRESS 






1 
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29 



designer's 
Notebook 



Logic-farnily translation 




ROBERT GROSSBLATT, 

CIRCUITS EDITOR 



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EVERYBODY HAS HIS FAVORITE LOGIC 

family. Some like the familiarity of 
TTL and have never given CMOS a 
chance since the bad days of the 
CMOS "A" series devices. On the 
other hand, some like CMOS and 
think that anyone hung up on TTL 
is from the stone age. DTL and RTL 
users are primarily history. 

The truth of the matter is that 
both TTL and CMOS are going to 
be around for a while because 
each has advantages and disadvan- 
tages. If you look at enough sche- 
matics, you'll see that many circuit 
designers routinely mix both logic 
families in the same electronics 
package. 

There are several considerations 
to keep in mind if you want to do 
the same thing in your own de- 
signs. Mixing logic families re- 
quires that you pay attention to the 
voltage at which they change state. 
TTL parts have much stricter re- 
quirements than CMOS. A TTL low 
state has a maximum voltage of 
about 0.8, and a TTL high state has 
a minimum voltage of 2.4. CMOS, 
on the other hand, is much more 
flexible. A low is usually defined as 
less than half the supply voltage, 
and a high is more than half the 
supply voltage. 

If you're working with a five- 
volt-only circuit, mixing TTL and 
CMOS is simple. As you can see in 
Fig. 1-a, driving a single TTL input 
with a CMOS output requires 
nothing more than connecting the 
two parts together. Going from 
TTL to CMOS, however, requires a 
bit more thought. Assuming a five- 
volt supply, the TTL high output 
can be as low as 2.4 volts. That's 
slightly below the point at which 



+5V 




INPUT < 



) OUTPUT 



FIG.I 



INPUT 
O 



CMOS 




-•-+10V 




the CMOS input will change state, 
so there's no guarantee that the 
circuit will work correctly. The so- 
lution is to add a pull-up resistor of 
about 4.7K, as shown in Fig. 1-6. 
The exact value of the resistor de- 
pends on the type of TTL you're 
using (74, 74S, 74LS, etc.), but a 
value of 4. 7K at least will get you in 
the ballpark. 



Different supply voltages 

Things get even more tricky if 
the CMOS and TTL halves of your 
circuit are powered by different 
voltages. Two readily available 
CMOS buffers (the 4049 and the 
4050) can translate the higher-volt- 
age CMOS output into something 
the TTL input can use. A sample 
circuit is shown in Fig. 2-a. To 
make the translation without in- 
verting the signal, use a 4050. 

Going from TTL at 5 volts to 
CMOS at, say, 10 volts, requires 
some voltage translation. We can't 
always do it the way we did in Fig. 
1-6 because the TTL output must 
be isolated from the higher CMOS 
voltage. 

There are many schemes to get 
the job done, but an easy one is 
shown in Fig. 2-6. A small-signal 
NPN transistor is used as a buffer- 
ing switch between the TTL and 
the CMOS parts, but keep in mind 
that the transistor will invert the 
signal from the TTL output. You 
can re-invert the signal by using 
another transistor or a spare 
CMOS gate. 

Fanout 

Before we leave the subject of 
logic-family translation, we must 
talk about fanout. If you're a reg- 
ular CMOS user, you're probably 
used to ignoring fanout limits al- 
together. The reason is that the in- 
put impedance of a typical CMOS 
part is so high that you can drive as 
many inputs as you want with a 
single output. The same is true 
when driving CMOS with TTL: A 
typical TTL output has more than 
enough current-capacity to drive 
any number of CMOS inputs. 



30 



Going the other way, however, is a 
bit of a problem. 

The reason is that most CMOS 
outputs simply can't deliver much 
current into a low-impedance TTL 
input. The number of TTL inputs 
you can drive with a CMOS output 
depends on the specific TTL part 
you're using. As a general rule you 
can drive more LS inputs than reg- 
ular or S inputs, but it's usually 
better to be safe than sorry. So 
don't drive more than two inputs, 
regardless of type. As a matter of 
fact, it's better not to drive more 
than one, and make it a 7404 or 
74S04. You'll have no trouble what- 
soever driving the single input and 
then following the standard rules 
for TTL-to-TTL fanout. 

If you anticipate designing many 
mixed-family logic circuits, work 
out each problem on a breadboard 
and standardize the design. By 
doing so, any time you're faced 
with the same problem, you'll 
have a debugged module you can 
drop in your circuit and solve the 
problem. And that will let you go 
on to more important things. R-E 



COMMUNICATIONS CORNER 



continued from page 27 



beams, stage hardware, and any- 
thing else that can reflect radio sig- 
nals. As shown in Fig. 1, any re- 
flected signals arrive at a wireless- 
microphone system's receiving an- 
tenna after a directly received one; 
hence, they are usually out of 
phase with the directly received 
signal. That phase difference can 
plunge the received signal level 
right into the noise level. As a re- 
sult, at one moment the audience 
may hear the performer, but at the 
next only the lips are seen moving. 
That's because, when the signal 
strength is too low, the micro- 
phone's receiver squelches to pre- 
vent the listener's ears from 
possibly being assaulted by the 
sound of random noise. 

Curing multiphase distortion 

Multipath distortion plagued 
wireless-microphone communica- 
tions until the introduction of a 



diversity antenna/receiver system 
that Shure {222 Hartrey Ave., Evan- 
ston, IL 60202), a manufacturer of 
high-performance microphone 
equipment, calls Diversiphase. 

The wonder of Diversiphase is 
that it wasn't invented earlier. Fig- 
ure 2 shows how it works. The sig- 
nal is received by vertical antennas 
a and b, which feed the receiver in 
parallel. To ensure that both an- 
tennas aren't affected by the same 
multipath signals, at least one an- 
tenna must be remotely located. 
Usually, 25-foot spacing between 
theantennas is best; the minimum 
spacing is 6 feet. 

However, note that antenna a 
feeds the receiver directly, where- 
as antenna b feeds the receiver 
through a 180° delay line that is by- 
passed by an electronic switch. 
The delay line is a half-wavelength 
(at the operating frequency) coax- 
ial section. 

The signals from the two anten- 
nas always add together, so that 
when they are in-phase, the total 
signal delivered to the receiver is 3 
continued on page 78 






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Audio 

Update 



The audio answerman 




LARRY KLEIN, 

AUDIO EDITOR 



IT OCCURRED TO ME RECENTLY THAT 

I've been answering consumers' 
hi-fi questions in various publica- 
tions for about 30 years! Of 
course, as times have changed and 
electronics has advanced, the 
nature of those questions has also 
evolved. In 1964, for example, I 
cautioned a reader that a metal 6L6 
tube was not an adequate replace- 
ment for a 6L6GC because the 
glass CC tube was designed to 
withstand the higher voltages to 
be encountered in the new audio 
amplifiers. 

Over the years I've handled 
problems of stereo and then quad- 
raphonic conversion, advised on 
the pros and cons of switching to 
transistor equipment, and so 
forth. Today those questions and 
their answers are no longer perti- 
nent, but new queries have arisen 
to take their place, so I've as- 
sembled a group of today's recur- 
rent Q's and A's in hope that they 
will be of some aid and comfort 
both to the novice and to the tech- 
nically beleaguered audiophile. 

On-off switching 

Q Should audio equipment 
• be left on permanently? 
borne audiophiles and manufac- 
turers claim that there is less wear 
on the equipment if it is left on, 
and that it also sounds better. 

A Several manufacturers of 
. preamps and accessories 
z advise that their equipment be 
§ switched on permanently. In fact, 
o some equipment is designed so 
£j that its circuits are powered at re- 
^ duced voltage even when switch- 
5 ed off, as long as the AC line cord is 
!r plugged in. The purpose in both 



32 



cases is simply to prevent audio 
thumps and other noises as the 
circuits charge at the moment of 
turn-on. When dealing with vac- 
uum tubes there's an additional 
reason not to have the equipment 
fully off. Tube filaments (like elec- 
tric light bulbs) tend to suffer 
stress from turn-on surges. If a 
tube is always on (with reduced 
filament voltage), thermal shock is 
reduced, and the tube's filament 
life is extended. 

Aside from noise and longevity, 
some manufacturers claim that 
there is a sonic advantage in hav- 
ing their equipment constantly 
on. That may be, but my feeling is 
that any design that needs to be 
permanently powered to avoid a 
long warm-up drift needs to be 
gotten back to the drawing board 
as quickly as possible! In any case, 
most manufacturers would advise 
you to turn off your audio equip- 
ment when you don't plan to use it 
again for several hours. 

Separate speakers 

Ql have been told that you 
. should use one type of 
speaker for classical records and 
another for rock. Do you agree 
with that idea? 

A Absolutely not! Every speak- 
• er system should deliver an 
accurate acoustic analog of the 
electrical signal provided to it by 
the amplifier. Those pushing the 
concept of different speakers for 
different music are saying, in 
effect, that certain types of music 
sound best with speakers whose 
frequency-response curves, dis- 
persion, distortion levels, etc. de- 
viate from the ideal. 



It seems to me that if each musi- 
cal instrument in a band or or- 
chestra has been recorded with a 
specific loudness level relative to 
the other instruments in that band 
or orchestra, you want your speak- 
ers to reproduce those levels accu- 
rately, no matter what kind of 
music is involved. For example, if 
the recording has been engi- 
neered so that the brass has an 
extra "nasal" quality, the bass extra 
"sock," and the string extra "bite," 
a speaker with a flat response will 
deliver those qualities — neither 
more nor less. In other words, you 
want a speaker system that is neu- 
tral, rather than having a specific 
built-in tonal quality. When a 
speaker system injects its own to- 
nal qualities — such as an upper- 
mid range boost — into the music, 
some program material may sound 
"better" — but on most program 
material the contribution will be 
inappropriate and will only be 
heard as coloration. 

I can see a situation in which a 
speaker that does a fine job of re- 
producing string quartets is not 
suitable for rock, but only because 
it lacks the acoustic-output ca- 
pability to achieve the desired 
sound-pressure levels. Achieving 
an adequate loudness level for 
rock or contemporary electronic 
music can drive your amplifier, 
your speakers, or both into distor- 
tion. The distortion may be due to 

(1) inadequate amplifier power, 
low speaker efficiency, or both, or 

(2) inadequate power-handling ca- 
pacity on the part of the speakers. 
In such a case, other speakers with 
greater efficiency and power-han- 
dling capacity would, of course, 



do a better job. However, all other 
performance criteria in respect to 
frequency range and smoothness, 
distortion, dispersion, etc., con- 
tinue to be valid. 

For that reason, a speaker that 
can deliver the high volume levels 
desirable for rock reproduction, if 
it is in truth a high-fidelity re- 
producer, should do just as good a 
job reproducing the more moder- 
ate levels of a string quartet. 

Tape-dub overload 

QWhen I dub some of my 
• records onto cassette, sec- 
tions of the tape (usually at the 
beginning) suffer from a sort of 
breakup in the sound every sec- 
ond or so. When I listen to the 
disks themselves during dubbing 
or later, they sound fine. What's 
wrong? 

A The records you are trying to 
■ dub are probably warped 
sufficiently to cause severe vertical 
deflection of your phono stylus 
during play. That produces a very 
strong, very low frequency signal 
that overloads your tape (or cas- 
sette) deck's electronics. The rec- 
ords themselves sound fine when 
heard through your system proba- 
bly because the subsonic warp sig- 
nal is either handled without 
overload or it is filtered out by 
components following the tape- 
output jack in your equipment. 
You can test my hypothesis by 
playing the problem disks again 
and noting whether warps dis- 
place the phono stylus toward the 
cartridge body and whether the 
warps coincide with the taped 
overload distortion. 

Dubbing Dolby 

QWhen copying a Dolby-en- 
• coded tape from one deck 
to another, is it better to decode 
the tape playing on deck A and re- 
encode it when recording on deck 
B, or to record the tape from deck 
A to deck B without decoding and 
re-encoding? 

A You'll achieve the best re- 
• suits in duplicating Dolby- 
processed tapes if you decode the 
signal during playback and re-en- 
code it while copying. In other 
words, the Dolby circuits should 
be switched on in both machines. 
If you were to copy Dolby-pro- 
cessed audio material with the de- 



coding and encoding circuits 
switched off, the signal is likely to 
be recorded by the second ma- 
chine at a different level than on 
the original tape. That can confuse 
the Dolby-decoding circuits dur- 
ing playback of the copied tape 
because the Dolby reference level 
has been shifted. The result will be 
less noise reduction and some 
high-frequency boost (or loss) in 
playback of low-level signals. 

Power and volume loss 

Q Although I have a CD play- 
■ er, I need a record player 
tor my 10-year collection of LP's. I 
recently replaced my old phono 
cartridge with a new high-quality 
unit, but now the power fed to my 
speakers is much lower on phono 
than on tape or tuner. Exactly what 
is the problem? 

A Variations on that question 
. have appeared in my mail at 
least twice a' month for many 
years. The problem — and it really 
isn't a problem — is a loss (or a 
gain) in volume resulting from a 
change in equipment: phono car- 
tridge, tape deck, CD player, 
tuner, preamplifier, power ampli- 
fier — in fact, any component. 

The "problem" arises partially 
because many audiophiles mis- 
takenly believe that volume con- 
trol setting correlates directly with 
amplifier output power. It does 
nor.' Think of an amplifier's volume 
control as a handle on a water 
faucet. If the water pressure (sig- 
nal voltage) is very high, then a 
slight twist will deliver a high vol- 
ume of water (sound); if the pres- 
sure is lower, then the faucet has to 
be opened further to get the same 
volume of water flowing from it. In 
the case in point, the new phono 
cartridge obviously delivers less 
signal to the preamplifier for a 
given record-groove velocity than 
the previous model. 

To determine whether the out- 
put level of a phono cartridge is 
adequate, play a record at the 
loudest volume at which you 
would ever normally listen to it, 
and then, without touching the 
volume control, lift the tone arm 
with its cue control. Listen for 
noise from the phono-preamp 
stages. If you don't hear hum, 
hiss, or RF buzz, phono gain is 
within the proper range. R-E 



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"If you're going to learn 

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34 




Stephen J. Simcic 

Vice President, Academic Affairs 



W ou've probably seen adver- 

JLtisenii'iifs from other 
electronic schools. Maybe you think 
they're all the same. They're not! 

CIE is the largest independent 
home study school in the world that 
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Meet the Electronics 
Specialists. 

When you pick an electronics school, 
you're getting ready to invest some lime 
and money. And your whole Future 
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Thai's why it makes so much sense 
to go with number one , . . with the 
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There's no such thing as 
bargain education. 

If you talk with some of our 



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We don't promise you the 
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and staff are dedicated to that. 
When you graduate, your diploma 
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Because we're specialists 
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At CIE, we've got a position of 
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of the ways we hang onto it . . . 

Programmed Learning 

That's exactly what happens with 
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CIE understands people need to learn 
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1311) YOU KNOW THAT WITH A .STANDARD 

FM-broadca$l receiver you can only hear 
part of the signals available on that band? 
The rest, called SCA {Subsidiary Com- 
munications Authorization) transmis- 
sions, are hidden away on subca triers and 
are intended to be received only by certain 
segments of the public. 

SCA originated with the founding of 
the S8-108-MHz band in the 1940's. It 
was intended as an income producer to 
help FM stations financially until the band 
became economically viable. It has been 
used for various purposes, such as back- 
ground music without commercials for 
restaurants and offices, for medical news, 
for second-language programming, and 
for radio reading and news services for the 
visually handicapped. 

In this article we are going to explore 
the world of SCA. We'll discuss, what it 
is, what makes it possible, and what types 
of programs and services make use of it. 
We'll also show you how to build an FM 
stereo/SCA receiver that will let you tune 
in to all of the signals on the FM band. 

But before we get too far along, it 
would be helpful to have an understanding 
of FM-radio basics. Let's take care of that 
step first. 

FM-radio basics 

An FM {Frequency Modulation) signal 
is simply any RF (fladio Frequency) sig- 
nal whose instantaneous frequency is de- 
termined by the modulation. The 
deviation of an FM signal is the compo- 
nent of change in carrier frequency that is 
determined by the amplitude (primarily) 
and frequency of the modulating signal. 
In the U.S., FM broadcast stations are 
permitted ± 75-kHz deviation, which is 
defined as 100% modulation. Both a 20- 
Hz audio signal and a 15-kHz audio signal 
can produce 75-kHz deviation because it's 
the combination of the frequency and the 
amplitude of the modulating signal (pro- 
gram audio) that determines the devia- 
tion. If one volt of fixed-frequency audio 
produced ± 75-kHz deviation, then one 
tenth of a volt would produce ±7.5-kHz 
deviation. Although deviation and modu- 
lation frequency are independent varia- 
bles, the ratio of deviation to modulation 
frequency is called the modulation index, 
or p, where 

P = deviation/modulation frequency 

in a typical FM-broadcast situation, 
with a I -kHz audio signal at 50% modula- 
tion (37.5-kHz deviation), p = 37,5 
(37.5 kHz/ 1 kHz). 

It's noisy 

Because the ear is most sensitive to 
high-frequency noise, and because the 



SCA/FM STEREO 

RECEIVER 



SCA/FM STEREO 
RECEIVER 



• STEREO 

Z POWEB 



TUNE 



FM 

SCA 







ON 



TUNING 



DOC 



POWER 



VOLUME 



PHONES 



Tune into the "hidden" signals on your FM dial 
with this SCA receiver. 

RUDOLF GRAF and WILLIAM SHEETS 



FCC wanted FM to have the best possible 
signal-to-noise ratio, FM broadcasting in- 
corporates a system of prcemphasis/ 
deemphasis equalization, whose param- 
eters are based on the fact that the high- 
frequency energy of the sounds that are 
commonly part of programming de- 
creases at an almost fixed rate per octave 
above 1000 Hz. (That was before the era of 
electronic instruments.) That allows the 
high frequencies to be preemphasized be- 



fore transmission, and mirror-image 
deemphasized at the receiver. The end 
product is a "flat audio response"; 
however, noise generated anywhere be- 
tween the preemphasis and the deem- 
phasis (such as atmospheric noise) is 
attenuated. Because the equalization re- 
flects nature's own frequency charac- 
teristics, it is therefore possible to 
preemphasize say. a concert orchestra that 
is reading 100% modulation on a VU 




WARNING! 



SCA is not a broadcast service, and 
SCA transmissions are not intended 
tor reception by the general public. As 
a result, SCA transmissions may be 
governed by Section 605 of the FCC 
Rules, which forbid unauthorized indi- 
viduals from receiving such communi- 
cations and using them for their own or 
other's profit, or divuiging their con- 
tents, intent, or meaning to any other 
unauthorized individual. 

Many for-profit services make use of 
SCA, and reception of those in most 




cases is permitted by paying subscrib- 
ers, and under certain circumstances, 
only. Some not-for-profit services do 
make use of SCA also, however, such 
as those providing assistance to the 
blind. It may be possible to receive 
those without obtaining prior permis- 
sion or paying a subscription fee, as 
long as the terms of Section 605 are 
observed. We advise you to contact 
the approriate programmers in your 
area for more information and to ob- 
tain any necessary authorizations. 



> 

o 

c; 
w 



CD 



39 



meter (which indicates average rather 
than peak power) without worrying that 
the preemphasi/.ed highs will cause over- 
modulation of the transmitter. 

Electronic instruments and "'signal 
processors" that came along many years 
after the founding of the modem FM band 
were to interfere with the established pre- 
emphasis/deemphasis concept; however. 
the equalization is still required to ensure 
optimum signal-to-noise ratio, lalthough 
it can be modified to accommodate FM- 
Dolby transmissions). By the way. if FM 
preemphasis/deemphasis noi.se reduction 
sounds similar to Dolby-B tape noise re- 
duction it's because they are similar in 
overall concept. Dolby simply "floats'' 
the high-frequency reference level. 

Pre-emphasis/de-emphasis of some 
kind is used in all forms of FM communi- 
cations, including SCA. That is, the FM 
si una I has it. and so docs the SCA signal. 



Because the earliest FM detector was 
also an AM detector it was sensitive to 
AM atmospheric noise t static), and so re- 
ceivers used IF I i miter ampliliers to clip 
the amplitude level of the IF signal so that 
most AM variations — including those 
caused by mullipath reception— we re 
eliminated before the signal was detected. 
Even though modern FM detectors barely 
respond — if at all — to AM signal varia- 
tions, receivers still use IF limiting to 
ensure minimum AM noise, and in par- 
ticular, to eliminate many troublesome 
effects caused by multipath reception. 

FM bandwidth 

The occupied bandwidth of an FM sig- 
nal, at first glance, appears to be simply 
the peak-to-peak deviation. However, that 
is not always true. A 75-kHz deviation 



FM broadcast signal, for instance, re- 
quires somewhat more bandwidth than 
simply the peak-to-peak deviation. Ob- 
viously, it is important to know the re- 
quired bandwidth for various reasons, 
among them channel spacing, necessary 
receiver bandwidth, and signal-to-noise 
ratio considerations. 

For signals with a very high modulation 
index, the necessary bandwidth is very 
close to the peak-lo-peak deviation. As an 
example, that would be true for a I009r- 
modulated FM signal (75-kHz deviation 
in commercial broadcasting) with low au- 
dio-frequency modulation (on the order of 
20 Hz, for example). However, the situa- 
tion changes for signals with a low modu- 
lation index. At a modulation index of 10 
the bandwidth required would be about 
2.b' times the peak-to-peak deviation (75 
kHz), or 210 kHz, At a modulation index 
of 5 (as would result from a 75-kHz signal 
with 15-kHz audio modulation) about 3.3 
times the peak-to-peak deviation, or 247 
kHz. would be required. 

That increased bandwidth is due to the 
sidebands generated in FM. The side- 
bands, as in the AM case, arc separated by 
the modulation frequency from the car- 
rier. However, depending on the modula- 
tion index, the sidebands vary in 
amplitude. They appear, reach a max- 
imum, then, at higher modulation in- 
dices, some sidebands disappear. In fact. 
the carrier disappears at a modulation in- 
dex of 2.4. That means, if we apply a tone 
of about 31 kHz to an FM transmitter and 
adjust the level of the tone to produce a 
deviation of 75 kHz, the carrier will actu- 
ally null out. Of course, the FM signal has 
not disappeared — all of its energy is now 
contained in sidebands spaced 31 kHz 



from the carrier — at ± 31 kHz, ± 62 kHz. 
±93 kHz. etc. 

While the mathematics required to de- 
scribe sideband amplitude and hence re- 
quired bandwidth arc very complex . a rule 
of thumb that works out relatively well in 
practice for low distortion is that the re- 
quired receiver bandwidth is approx- 
imately twice the deviation plus the 
highest modulating frequency. That fig- 
ures out to about 240 kHz for an FM- 
stereo/SCA receiver. Note that FCC chan- 
nel band widths are 150 kHz, with 50 kHz 
guardbands between assigned channels. 

As another example, commercial 2- 
way FM radio used for police, fire, taxi- 
cab, etc. as well as 2 meter FM radio use 
±5-kHz deviation with audio restricted to 
3 kHz (3000 Hz). Receivers for those ser- 
vices use 13-kHz bandwidth IF filters. 
That, of course, is twice the deviation plus 
the highest modulation frequency. 



The FM signal 

The various components of a stereo FM 
broadcast signal are as follows: 

• Audio baseband (0-15 kHz). That is a 
monophonic signal comprised of the sum 
of the left and the right (L+R) audio 
channels; it is the program audio received 
by a a monophonic FM radio. 

• Stereo baseband (19 kHz and 23-53 
kHz). That consists of the pilot carrier at 
19 kHz. and a DSB (Double Sidcfland) 
suppressed carrier AM signal centered at 
38 kHz. The 38-kHz carrier is sup- 
pressed, and the low-level pilot carrier at 
19 kHz is used by the receiver to regene- 
rate the 38 kHz suppressed carrier. In that 
way the 38 kHz DSB signal is recovered 
and detected. That signal is comprised of 
the difference between the left and right 



y 

z 
O 
EC 
(— 
O 



□ 
< 
tr 



POIfNTIOMHER ■*■ 




HIGH PASS 
FILTER 



SCA 
DETECTOR 



MPX 
DECODER 



-r^T 



FIG. 1— OUR SCA RECEIVER is shown here in block diagram form. 



40 



PARTS LIST 



Resistors Vt watt, 10% unless 

otherwise noted 
R1, R3. R7, R8, R10, R46, R6Q— 100.000 

ohms 
R2— 47,000 ohms 
R4, R25, R28. R68, R7Q— 100 ohms 
R5, R31, R32, R35— 470 Ohms 
R6. R21, R39— 150 ohms 
R9.R1 1—220 ohms 
R12, R14, R18— 2200 ohms 
R 13— 3500 ohms 
R15, R30. R56, R57, R62. R66, R76— 

1000 ohms 
R16, R23. R27, R36-R38. R40, R43, 

R45. R49. R54, R58, R59, R61 — 

10,000 Ohms 
R17— 1 megohm 
R19, R67, R69— 10 ohms 
R20, R24, R29. R33— 330 Ohms 
R22, R26— 33,000 Ohms 
R34, R42. R44— 22,000 ohms 
R41, R47, R51-R53. R64, R65— 4700 

ohms 
R48, R50— 18,000 ohms 
R55, R63— 15,000 ohms 
R71-R75-1 0.000 ohms, potentiometer 
Capacitors 

C1. C7, C17— 2-18 pF trimmer 
C2, C5. C6. C8, C9, Gil, C13-C15, C18, 

C20-C26. C28, C30-C34— 0.01 jiF, 

ceramic disc 
C3. C4, C56 — 470 pF, ceramic disc 
C10, C16, C37—1O0 pF, silver mica 
C12, C29, C35, C36, C39, C47, C49, C59, 

C62— 10 (J.F, 16 volts, electrolytic 
C19— 8 pF, silver mica 
C27-not used 
C38— 3-40 pF, trimmer 
C40-C43— 220 pF, silver mica 
C44--0.001 jiF, Mylar 
C45, C60, C63— 0.1 |j.F T Mylar 
C46, C51— 0.047 |i.F. Mylar 
C48, C52— 0.0022 ^F, Mylar 
C50, C53-— 0,22 (xF, Mylar or tantalum 
C54— 0.47 (iF, Mylar or tantalum 
C55, C65 — 470 pF, silver mica 
C56, C57— 0.022 jxR Mylar 
C58. C61, C64 — 470 tiF. 16 volts, elec- 
trolytic 
Semiconductors 
IC1— LM3189N FM receiver IF system 

(National) 



audio channels (L-R). [n a stereo re- 
ceiver, the L — R and L + R signals are 
combined in such a way as to recreate the 
left and right audio channels. 

• ARI (Automobile /fadio /reformation) 
subcarrier(57 kHz). That is a narrow-band 
channel used for traffic bulletins. Ori- 
ginated in Europe, that service has been 
recently implemented here and may be- 
come popular in the future. It is currently 
used on a trail basis in some major metro- 
politan areas. 

• SCA subcarrier (most often 67 kHz 
and/or 92 kHz). The SCA subcarrier is 
used for "hidden" radio programs, back- 
ground music, and digital data transmis- 
sion. The signals are FM with ±7.5-kHz 
deviation maximum. SCA is not a high 
fidelity service; its audio-response band- 



1C2— LM565 phase-locked loop (Nation- 
al) 

IC3— LM1310N FM stereo demodulator 
(National) 

1C4, IC5— LM386 audio amplifier (Nation- 
al) 

Q1 , Q2^t0673 dual gate MOSFET 
transistor 

Q3-Q5— 2N3563 NPN transistor 

Q6, Q7— 2N3565 NPN transistor 

DJ. D2, D4— MV2107 varactor diode 

D3— 1N757 diode 

D5— 1N4001 diode 

LED1— jumbo red LED 

LED2— jumbo green LED 

Other components 

Li. L3, L5— see text 

12, L4— 1.8 n-H 

L6, L7— 18 m-H 

CF1-CF3— 10.7 MHz ceramic filter 

J1— stereo headphone jack 

J2-J8 — phono jacks, RCA type 

S1— SPST toggle switch 

S2— 3P4T rotary switch 

Miscellaneous— PC board, No. 20 solid 
uninsulated wine for winding L1 . L3, and 
L5 (18 inches total required), wire, sol- 
der, hardware, knobs, cabinet, etc. 

The following are available from North 
Country Radio, P.O. Sox 53, Wykagyl 
Station, NY 11804: Kit consisting of 
PC board and all PC-board mounted 
parts (jacks, switches, 05, LED's, 
power-supply components, etc. not 
included), $75.00 plus $2.50 postage 
and handling; Etched and drilled PC 
board, $12.50 plus $2.50 postage and 
handling. NY residents please add 
appropriate sales tax. 



PARTS LIST— POWER SUPPLY 

C67— 2200 m-F, 25 volts, electrolytic 

C68— 0.01 u.F, ceramic disc 

C69 — 0.1 u.F, ceramic disc 

C70 — 470 m-F. 16 volts, electrolytic 

T1 — 117-voit primary, 16-18 volt 500-mA 

secondary 
IC6— LM7812 Ihree-terminai regulator 
D6-D9— 1N4001 diode 



width is limited to about 5000 Hz. 

Our immediate interest, of course, is in 
the SCA signal. It is normally used as an 
auxiliary, income- producing service by 
the operators of an FM broadcast station. 
However, we do not get something for 
nothing. Modulating any of an FM chan- 
nel's sub-carriers reduces the maximum 
modulation available for the main audio 
channel. In the case of SCA, modulating 
one subcarrier of a stereo signal uses up 
about 10% maximum of the total 75 kHz 
deviation (100% modulation). In practice, 
that reduces the main channel's signal 
strength by about 1 dB. Normally, such a 
drop in signal level would not be notice- 
able. However in areas with crowded FM 
bands, every dB counts in the race for 
ratings, and revenue. Stations in those 



locations are likely to think twice about 
using both available SCA subcarriers. 
which would cost about 2 dB in signal 
level, let alone ARI, etc. On the other 
hand, leasing those subcarriers can be a 
significant source of income for the li- 
cense owner, 

SCA is noisy 

At best, the SCA of a stereo-FM signal 
can represent only 10% of the total FM 
transmission; hence, the received SCA 
signal is unusually weak, and therefore 
prone to be noisy. Also, depending on the 
design of the receiver and the care taken 
with the SCA signal at the transmitter, the 
received SCA can suffer from "splatter" 
or "spillover sputter" from an FM sta- 
tion's main audio channel. The splatter 
and sputter is usually 30-40 dB below the 
SCA audio, but that's a level that can be 
heard as intermittent "noise." With prop- 
er filtering in the receiver, however, main- 
channel interference to the SCA caused 
by the receiver's circuits — not by the 
transmitter — can be attenuated low 
enough so it can't be heard. 

In fact, the SCA channel — particularly 
when received on an SCA-dedicated re- 
ceiver — is good enough so that in addition 
to background music it has been used for 
digitized stock-market quotes, digital- 
data transmission, telemetry, radio pag- 
ing, and slow-scan color TV. And at pres- 
ent, out in California (where else?) the 
SCA is being used to distribute informa- 
tion and advertising to computer users in 
the Los Angeles area. 



Receiving SCA 

A block diagram of our SCA/FM-ster- 
eo receiver is shown in Fig. I. The com- 
plete schematic is shown in Fig. 2. The 
circuit uses a MOSFET RF amplifier 
whose input and output (mixer) circuits 
are tuned by varactor diodes. Those varac- 
tors can be thought of as voltage-variable 
tuning capacitors. The DC tuning voltage 
is variable from about 1.5- to 8- volts DC. 
The local oscillator operates at the tuned 
signal frequency plus 10.7 MHz. The os- 
cillator is also tuned by means of a varac- 
tor diode. The three varactors are biased 
by a common DC bias line, so as to simul- 
taneously tune the RF amp, mixer, and 
oscillator circuits. 

The mixer output circuit is tuned to 
10.7 MHz and feeds an IP preamplifier 
that has a gain of about 30 dB. This pre- 
amplifier uses two transistors and three 
fixed-tuned ceramic IF filters centered at 
10,7 MHz. Since the filters are fixed- 
tuned, no alignment is necessary. That 
eliminates the need for complex sweep 
alignment and allows a novice builder to > 
automatically get the good IF-bandpass ^ 
response necessary for SCA/FM-stereo c: 
reception. -i 

A National LM3189N FM receiver IF 3j 
system (an RCA CA3I89E can be sub- 5 



41 







FIG. 2— THREE OF THE INDUCTORS shown in this schematic diagram must be wound by hand. Even 
so. they are simple to make; complete details will be given in the next installment of the article. 



CO 
O 

z 
O 
rr 

t- 
o 

LU 



o 

Q 
< 

rr 



stiluted) iC. ICI. performs limiting and 
quadrature detection of ihe FM signal, 
and recovers the original audio baseband. 
Thai IC offers high gain, good limiting, 
and low-distortion detection. It also 
provides an AFC voltage to correct drift in 
the local oscillator and to aid in tuning a 
selected station. Due to the very high 
gain, layout is very critical and we strong- 
ly recommend using the PC layout that 
will be presented next lime. Otherwise 
you may leave yourself open to RF-in- 
slability problems. 



The audio output of the LM3I89N is 
fed to an 2N3565 audio amplifier, which 
delivers an output level of about 3-volts p- 
p. That baseband audio is used to feed the 
phase-loeked-loop SCA detector (an 
LM565) and the FM -stereo detector (an 
LM1310NJ. 

A high pass and twin-T R-C filter de- 
signed to reject frequencies below 50 kHz 
passes the SCA carrier to the LM565. The 
output of the IC is the VCO control volt- 
age, which follows instantaneous fre- 
quency variations of the 67- or 92-kHz 



subcarrier. That output (about 50 to 100 
millivolts p-p) is the SCA audio. It is 
passed through a low-pass de-emphasis R- 
C network to remove high-frequency 
noise. An SCA audio amp (a 2N3565) 
amplifies the signal to about 500-rnV p-p, 
which is sufficient to fully drive the audio 
power amplifiers. 

The LM 13 ION is designed to accept the 
baseband audio and reproduce the origi- 
nal L and R audio channels. Baseband 
audio of about 2-3-volts p-p is fed to the 
LMI310N and L and R audio signals ap- 



42 




pear at the outputs. Shunt connected ca- 
pacitors provide de-emphasis. An LED 
can be connected to the decoder to indi- 
cate stereo reception. 

A 3P4T (three pole. 4 throw) switch 
selects among FM (stereo in the case of 
stereo broadcasts), SCA, tune, and auxili- 
ary positions for input to the dual power 
amps. In the tune position, FM main 
channel audio is input to one of the amps 
while SCA audio is input to the other. 
That makes tuning in an SCA subcarrier 
easier; more details will be provided when 



we talk about using the receiver. In the 
auxiliary position the unit becomes a 
power amp and will accept an external 
input via its link in jacks. 

The dual power amps are identical and 
are built around a pair of LM386N's. 
Power output is 'A watt (500 mW) per 
channel. That is sufficient to drive a pair 
of small speakers, but we recommend 
using stereo headphones for best results. 
If desired, the LM3S6N amps can be 
omitted and the outputs fed to the line 
inputs or tuner inputs of an audio system. 



About 500 mV into a 10k load is available 
at the l ink out jacks. 

More detail 

Looking at the circuit in more detail. 
FM signals from the antenna are applied 
between the tap on LI, which is the anten- 
na coil, and ground. The antenna coil is 
tuned by CI and varactor Dl to the signal 
frequency. The varactor has a variable 
back bias of 1.5 to 8 volts across it. That 
will sweep its capacitance from 15 to 30 
pF When that capacitance is added to the 



> 

Q 

C 



CO 
CO 



43 



stray capacitance on the board and the 
input capacitance of Ql . it yields a tuning 
range of 87—109 MHz; that is mure than 
sufficient to cover the complete FM 
broadcast band. 

Capacitor C2 provides an RF ground 
and allows DC bias from the tuning-volt- 
age line to be supplied through Rl.lt also 
cleans up any noise present on the tuning 
voltage line. No DC current Hows in Rl. 
and therefore there is no voltage drop 
across that component. 

The tap on LI is placed so that QI sees a 
high input impedance. Transistor Ql is a 
40673 MOSFET device with a noise fig- 
ure of 4 dB or less ( typically 2-3 dB at FM 
frequencies): that ensures high' sensitivity 
and there is no base-emitter junction to 
cause unwanted rectification of strong sig- 
nals. Resistor R4 and capacitor C3 
provide biasing and RF grounding for 
Ql"s source terminal. The 02 terminal, is 
biased at about +4 volts by R2 and R3. 
and C4 bypasses that terminal to ground. 
The gain of the stage may be controlled by 
reducing that bias to — 2 volts (cut-off) for 
AGC purposes. However. AGC was not 
necessary in the receiver, and was not 
used. Tire drain is biased through R6 and 
L2 to about + 1 1- volts DC. Drain current 
(which is exactly equal to the source cur- 
rent) is about six to eight milliamperes. 
Resistor R5 limits the stage gain to 
about 6 times. That is the optimum 
amount of gain to ensure circuit stability: 
it is quite adequate to override mixer 
noise, yet not so high as to unnecessarily 
overload the mixer on strong signals. Fur- 
ther, it allows about a 3-dB margin for 
mistracking and errors in alignment of the 
tuned circuits. 

Capacitor C6 couples the RF signal to 
L3. which serves to tune the mixer input. 
Capacitor C5 is an RF bypass and resistor 
R6 decouples the RF stage from the + 12- 
volt line. 

The mixer-input tuned circuit is tuned 
by C7 and D2, with stray circuit capaci- 
tances once again playing a role. Ideally, 
total capacitance in the circuit is exactly 
equal to that in the antenna circuit. 
However, the operating Q is a little higher 
(about 30). The overall RF" bandwidth is 
about 2 to 3 MHz. which provides quite 
adequate image rejection — about -30 
dB or better. 

The mixer is driven by a signal of about 
3-4 volts p-p on G2 of Q2. Since the 
transeonductancc of the 40673 is a func- 
tion of the G2 voltage with respect to the 
source, the local oscillator (more on that 
<fi in a moment) signal in effect modulates 
y the transconductance of Q2. That results 
O in the 40673 acting as a inker. Resistor 
jE RH returns G2 to DC ground. Resjstor R9 
Jr] and capacitor C9 provide about a 0.6-volt 
jjj bias, which places both gates at about 
O -0.6 volt, with respect to the source ter- 
g minal. The power gain of the mixer (the 
rr ratio of the IF signal at 10.7 MFlz to the 





16-lBv/50QmA 




k^Dfi 






















117 
VAC 








09_V 


141 
1N40Q1 












1 




1 


IC6 
LM7812 


o 


fai 


4- 

3> C67 

220%F 
25V 


™ 








C70 « 

471V F 

16V 








-C6B 


C C69- 




































I 



FIG. 3— THE CIRCUIT REQUIRES a regulated 12-volt power supply. The one shown here fills the bill 
nicely. 



RF input signal) is about 12 to 15 dB, 
depending on local oscillator drive level. 

The local oscillator uses a2N3563 tran- 
sistor. Q3. whose operating point is 4 
volts al 1.5 milliamperes. That operating 
point is established by the network com- 
prised of RI2. R13, RI4. and R15. Note 
that the local oscillator is actually a volt- 
age controlled oscillator set up to be in the 
common-base mode at RF frequencies. 
At such frequencies. C!4 grounds the 
base of Q3 . 

Inductor L4 is an RF choke that is used 
to teed DC voltage to the collector of Q3. 
Capacitor CIS couples the tank circuit 
made up of L5, C17, and D4 to (he collec- 
tor of Q3. That tank circuit is used to 
determine the oscillator frequency, which 
should be 10.7 MHz above or below the 
signal frequency. In this receiver, the local 
oscillator operates 10.7 MHz above the 
incoming signal. Therefore, it must tune 
from about 98 to 120 MHz. "The spacing 
should be 10.7 MHz over the entire tuning 
range of 87-109 MHz, Resistors R16 and 
RI7 are used to couple the AFC correction 
voltage to the tuning line, eliminating the 
need for a separate AFC tuning diode. 
The value of R16 can be anything from IK 
to 100K, depending on how much AFC is 
desired. We used a 10K unit. 

As previously mentioned, L5 and CI9 
match the mixer to ceramic filter FLI. 
Those components also help prevent un- 
wanted VHF components from leaking 
into the IF stages, which could cause spu- 
rious responses. A ceramic filter is a 
piezoelectric device that is the equivalent 
of an IF transformer. It acts as a double- 
tuned transformer with a 1-dB bandwidth 
of 250 kHz, centered at 10.7 MHz. The 
device's insertion loss is about 6 dB. and 
its termination impedance is specified as 
330 ohms. 

The first IF amplifier is built around 
Q4. That transistor is biased by R22, R23. 
and R25 to about 2 milliamperes when the 
collector voltage is 4. Ceramic filter FL2 
couples Q4 loQ5, which is biased identi- 
cally to Q4. using R26. R27, and R28. 
Capacitors C21 and C22 bypass the emit- 
ters of Q4 and Q/5 respectively. The IF 
stages are decoupled from the power-sup- 



ply line by R32. R3I. C24, and C23, 
Resistor R30 is used to determine the op- 
erating points of Q4 andQ5. It results in a 
+ 4.5-volt supply to those stages, form- 
ing a voltage divider with R31 and R32. 
The IF signal is coupled to the I i miter/ 
detector stage ( IC1 and peripheral compo- 
nents) by FL3. The three ceramic filters 
shape the IF bandpass of the receiver. 
They are fixed tuned and no alignment is 
required. 

The gai n of Q4 and Q5 is about 26 to 30 
dB. That gives a total gain so far. from the 
antenna, of about 55 to 60 dB, ensuring 
that the front -end noise will cause limiting 
in 1CI. The maximum output of Q5 is 
about 0.25 volt, which is the saturation 
point, no matter how strong a signal is 
received: ICI can easily handle that with- 
out distortion. No AGC was found neces- 
sary in this receiver. 

Most the functions of an FM IF system 
are provided by ICI . That device includes 
a three-stage limiter, signal-level detec- 
tors, a quadrature detector, and an audio 
amplifier with optional muting circuit 
(squelch). It has its own internal reg- 
ulators for DC voltages, and can drive an 
external tuning meter. While we specified 
using a National LM3819N, an RCA 
CA3189E is pin-for-pin compatible with 
that device and can be used in its place. 
Use whichever IC is easiest for you to 
find. 

Input signal from FL3 is applied to pin 
I of IC I . R33 is a bias resistor and also 
terminates FLI. Capacitors C25 and C26 
are RF bypass capacitors. The 12-volt sup- 
ply line is connected to pin II of ICI by 
R19, C31. R39. and C32: those compo- 
nents provide RF decoupling as well. 
While they are not used in the receiver, the 
IC's squelch (mute) circuits must be ter- 
minated; R34. C28. C29. R35. and R36 
serve that function. 

An optional tuning meter can be in- 
stalled in the receiver. We chose not to do 
so, but if you do, install it at the junction 
of C30 and R37 as indicated in Fig. 1. 
Otherwise, the junction makes a good test 
point for aligning of the front -end's tuned 
circuits. 

continued on page 81 



44 



o 



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ROSS ORTMAN 




Versatile Digital Timer 



You don't need a fancy microprocessor-based timer to turn a device off and on 
several times a day. This easy-to-build and inexpensive timer will do it with no hassle! 






1IM1RS CONTROL EVERYTHING FROM SB- 

curity systems to computer systems to cof- 
fee makers — the list goes on and on. 
Timers vary in sophistication from simple 
mechanical devices to microprocessor- 
based controllers. But there is a middle 
ground. A low- cost module allows you to 
build a high-performance unit that oper- 
ates like a VCR timer, is inexpensive, and 
is very easy to build. The timer allows 
three on/off set points per day, and it can 
control any device that draws as much as 6 
amps of current. If the timer's output ca- 
pacity is insufficient, you can easily add 
an output switching device with greater 
capacity. The timer can be built for about 
$60 using all new parts. 

How it works 

The timer's schematic is shown in Fig. 
1 . The heart of the timer is the PCIM 2303 
LCD timer/clock module, made by PCI 
(Printed Circuits International, 1145 
Sonora Court, Sunnyvale, CA 94086). 
The 2303 module contains the timer IC, 
clock crystal, an LCD display, and all 
support components. It requires only 1.5 
volts and draws a maximum of 10 pA. 
Tli at low power requirement allows the 
module to be powered by a single A A 
battery, which makes it great for use in 
portable equipment. 

The module has a single output that is 
high during the on period and low during 
the off period. Because the output is 



powered by the module, it cannot deliver 
any appreciable current. Therefore the 
control voltage is fed to a transistor switch 
composed of Ql, Q2, R3, and R4. The 
switch circuit in turn controls IC1, an 
MOC3010 optocoupler, which isolates 
the power-control section from the rest of 
the circuit. 

The power-control section is composed 
of Triac TR1 , current-limiting resistor R5, 
and an MOV (Metal Oxide Varistor). The 
latter protects the triac and the op- 
tocoupler from power-line spikes and 
transients caused by highly inductive 
loads. 

The power supply is composed of Tl , 
Dl, and Ci; it provides nine- volts DC that 
powers the switch circuitry. It can also be 
used to trickle-charge a Ni-Cd battery. 
Although a regular lead-acid or alkaline 
battery will last for quite sometime, a 1.5- 
volt rechargeable battery will give best 
results. The 1-mA trickle charge supplied 
by optional components D2 and Rl 
should increase battery life indefinitely. If 
those components are not installed, never 
apply power to the unit without a battery 
in place, or damage to the PCIM 2303 
module may result. 

The specified Triac is rated at 6 amps. If 
that is inadequate for your application, a 
larger one can be used. Regardless of 
which Triac is used, it will generate heat, 
so provide an adequate heatsink and ade- 
quate ventilation to avoid overheating. 



Fuse Fl protects not only the transformer 
and circuitry, but also the Triac. If a de- 
vice tries to draw more current than the 
Triac can handle, the fuse will blow, thus 
saving the Triac from damage. If you use a 
Triac with a larger current rating, be sure 
to install a fuse of the proper size. 

Other types of power-control circuits 
are possible; several examples are shown 
in Fig. 2. An SCR-based circuit is shown 
in Fig, 2-a, and a relay-based circuit in 
Fig. 2-b. If you use a different circuit, be 
sure to isolate the timer module from the 
voltage being switched. And whether you 
use a relay, a Triac, an SCR, or some other 
device, be sure it can handle the max- 
imum current the device you want to con- 
trol will draw. 

Construction 

The timer circuit is simple enough to be 
wired using point-to-point techniques; 
but for a cleaner layout, PC boards can be 
used. You can purchase pre-etched and 
drilled boards from the source mentioned 
in the Parts List; alternatively, foil patterns 
for etching your own board are shown in 
PC Service. As shown in Fig. 3, the dis- 
play board contains the timer module and 
S1-S4. The main board, shown in Fig. 4, 
contains the power supply, the battery, the 
switching circuit and the output circuit. If 
you use a different output-switching cir- 
cuit you can alter the design of that board 
to fit your application. 



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FIG. 1— SCHEMATIC DIAGRAM OF THE TIMER. The PCIM 2303 timer module contains all timing 
circuits and an LCD display. 



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FIG. 2— AN SCR (a) OR RELAY OUTPUT (6) driv- 
er can be substituted for the triac output circuit 
in Fig. 1. 

Stuff the boards in the usual manner, 
starting with the low-profile components, 
and working up to the larger ones. The 
timer module contains CMOS circuitry, 
so handle it with care. Be sure to observe 
the polarities of capacitor CI and the sem- 
iconductors. Install the transformer last, 
making sure that it is installed correctly. 



An excellent case for the timer is men- 
tioned in the Parts List. If you use the 
specified case, note the limited clearance 
between the bottom of the PC board and 
the case. Be sure to insert a piece of fish- 
paper (or some other insulator), between 
the board and the bottom of the case to 
avoid shorts — and possible shocks. 

Note, in Fig. 4 and Fig. 5, the small 
strip of PC board material glued to the top 
of the main board behind the display 
board. That strip reduces stress on the 
module and prevents the display board 
from bending when the pushbuttons are 
pressed. The remainder of construction is 
straightfoward. In our prototype the mod- 



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MODULE 
OUTPUT 



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TIMER/ 
CLOCK 
MODULE 



FIG. 3— THE TIMING MODULE and four switch- 
es mount on the display board, which connects 
to the main board via three wires. 



ule (and the attached PC board with 
switches) is glued from behind to an 
opening in the front panel . 

Testing 

After mounting all components, in- 
spect your work carefully for open solder 
joints, solder bridges, etc. Correct any 
mistakes. 

Then insert a battery into the holder, 
being sure to observe polarity. Now press 
the set and man buttons simultaneously 
to reset the module. If the module doesn't 
display anything, re-check your wiring. 

After you get the module to reset, plug 
the line cord into an AC oudet, and plug a 
table lamp (or other electrical device) into 
SOI and press the man button. The light 
should turn on. If it doesn't, check the 
module's output pin. It should have about 
1 . 1 volts on it. If it does, make sure that Ql 
and Q2 are turning on and enabling the 
LED inlCl. If the LED is turning on, you 
should measure about 1.4 volts across it. 
If the LED does turn on, the problem lies 
with the AC portion of the circuit. Be very 
careful when troubleshooting the AC 
section, because it has 117-volts AC 
across it. Check for wiring errors; other- 
wise, the triac may be bad. 

After you get the circuit working, as- 
semble the case. The timer is now ready to 
go to work for you in whatever application 
you see fit. 

Operation 

Programming the timer is very similar 
to programming a VCR timer. At initial 
power-up, the device must be reset. That's 



46 



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FIG. 4 — STUFF THE MAIN BOARD as shown here. Three wires connect to corresponding points on the 
display hoard, as shown in Fig. 3. 



current time, which is indicated by a 
flashing colon. The programmed timer 
will now turn the device you connected on 
and off at the preset times. 

The man button allows you to override 
the present state of the timer manually. If 
the output is off when the man button is 
pressed, the output will tum on. Con- 
versely, if the output is on, pressing the 
man button will turn the output off. After 
pressing the man button, the state of the 
output remains constant until the man 
button is pressed again, or until a preset 
time forces the output of the timer into a 
different state. 

The man button controls another im- 
portant function. It can be used to override 
the pre- set times. For example, to over- 
ride the first on time, advance the set 
mode until the first on time is reached and 
press the man button. An A' will appear in 
the display; it indicates thai the first on 
time has been overridden. The timer will 
then ignore the locked-out set point until 
it is "unlocked" by repeating the lock-out 
sequence. 

Applications 

The timer is versatile, so its applica- 
tions are virtually limitless. As a stereo 
limer, the unit outperforms most commer- 
cially available systems. The timer could 
be programmed to turn your stereo on in 
the morning, turn it off just after you leave 
for work or school, tum it on just as you 
are getting home, and turn it off after you 
have gone to bed. 

The unit could also be used to control 
house lighting for convenience or se- 
curity. When used as a security device, a 



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STOP 

FIG. 5— THE COMPLETE TIMER CIRCUIT ap- 
pears as shown here. Trim the PC board so that 
it fits into the case properly, and Insert a sheet of 
Insulating paper between the board and the bot- 
tom of the case. 



accomplished by pressing the stir and 
man buttons simultaneously. Then the 
correct time must be entered, Press set 
once to enter the set mode; a flashing T 
will be displayed. Now set hours and min- 
utes by pressing the hrs and min buttons 
as appropriate. The displayed hours (or 
minutes) will advance once for each press 
of the button; if you keep the button 
pressed, the display will advance continu- 
ously at a rate of about two digits per 
second. 

By pressing the set button again, the 
first on time can be set in the same way 
that time is set. Then press the slt button 
again to set the first off time. By con- 
tinuing to press the set button, the second 
and third on and off times can be pro- 
grammed into the uoJt, After the third off 
time is set, pressing the set button once 
more returns the unit to displaying the 



! 







PARTS LIST 
All resistors are Vi-watt, 5% unless oth- 
erwise noted. 
H1— 4700 ohms 
R2— 470 ohms 
R3— 47,000 ohms 
R4 — 100.000 ohms 
R5— 180 ohms 
Capacitors 

Ct— 220 nR 16 volts, electrolytic 
Semiconductors 
IC1— MOC3010 Optocoupler (Radio 

Shack 276-134 or equivalent) 
D1. D2— 1N4001 rectifier diode 
Q1— 2N3904 NPN Transistor 
Q2— 2N3906 PNP Transistor 
TR1— 6-amp 400-voit Triac (Radio Shack 

276-1000 or equivalent) 
Other components 
B1 — 1.5 volts, rechargeable A A batlery 
F1— 6-amp, 250-volt fuse 
MOV1— 117-volt metal oxide varistor (Ra- 
dio Shack 276-568 or equivalent) 
S1-S4 — SPST, momentary, normally 

open 
SOI— chassis-mount AC receptacle 
T1— 6.3-volt 300mA transformer (Radio- 
Shack 273-1384, or equivalent) 
Miscellaneous: PCIM 2303 timer/clock 
module, chassis-mount fuse holder, bat- 
tery holder, line cord, case (Radio Shack 
270-286). 

Note: the following are available from 
Dakota Digital, R. R. 1, Box 83, Can- 
istota, SD 57012: display PC board, 
S3. 50; main PC Board, 59,95; 
PCIM-2303 module, $23.95; module 
and four pushbutton switches. S26.50. 
All orders add $1.50 for shipping and 
handling. South Dakota residents add 
appropriate sales tax 



house can be made to look "lived in" by 
turning the lights on in the morning for a 
preset time and turning them on and off 
several times during the evening. If sever- 
al timers were used to control different 
lights throughout a house, the effect 
would be even greater. 

Other items can be controlled. For ex- 
ample, you could turn your coffee pot on 
in the morning 10 minutes before you get 
up. Then you could always have your 
morning coffee first thing. You could also 
control your heating system with the 
timer, heating your house only while 
you're home and awake, and turning it off 
during the day while you're gone and at 
night while you're asleep. The money 
saved doing that will add up quickly. 

During the winter, in cold climates, the 
timer could be used to turn your car's 
engine-block heater on in time to warm 
the block up enough for safe usage. 

Of course, the PCIM 2303 can be used 
in many other applications. It's a versatile 
device and it can be used in countless > 
applications. Whether you' re replacing an § 
existing timer or designing a timer system g 
for a custom application, the PCIM 2303 



clockytimer module is the ideal starting 
point for many designs. R-E 



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47 



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HIGH 

DEFINITION 

TV 





The most important change in TV technology since it was invented 

is just over the horizon. 



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CREATED IJY NEON LAMPS AND VIEWED 

through a spinning spiral of holes in a 
Nipkow disc, the very first TV images 
were so crude that they barely allowed the 
viewer to distinguish light from shadow. 
Today we are much more fortunate — on- 
screen resolution of several hundred lines, 
both horizontally and vertically, permits 
us to read street signs, subtitles, and 
movie credits on color CRT's or LCD's. 

Even so, we're always aware that we're 
looking at a television picture, that is, a 
picture displayed on a screen. And when 
we can not discern the finer details in an 
image, no matter how hard we strain, the 
shortcomings of the current system be- 
comes evident. That is true whether the 
system in question is the NTSC system 
used in this country, or the slightly higher- 
resolution PAL and SECAM systems that 
have been adopted by most of the rest of 
the world. 

But help is on the way. Dramatic im- 
provements are on the horizon in the form 



JOSEF BERNARD 

of tfigh-Definition TV (HDTV) systems 
that will add realism and detail to the 
images we view for entertainment and in- 
formation. 

HDTV technology exists today; it is 
used, for example, in Hollywood for spe- 
cial-effects work in TV. By as early as 
1990, Japanese broadcaster NHK plans to 
have an HDTV system in place and opera- 
tional. And work here, in Europe, and 
elsewhere is progressing so fast that sys- 
tems may be in place worldwide shortly 
thereafter. In this article we'll examine the 
Japanese HDTV system and others, see 
how they evolved, and learn about what 
obstacles remain before they can become 
adopted for widespread use. 

HDTV criteria 

One of the goals of HDTV is to create a 
sense of realism for the viewer that's at 
least as good as that provided by motion- 
picture film. How 1 ? Tests have shown that, 
to overcome the " picture- in-a-box" effect 



of TV viewing, the image must subtend a 
viewing angle of at least 30°. To obtain 
such an angle, one could simply sit closer 
to the screen. However, at a distance of 
less than 7 times the image height, scan 
lines become noticeable and give the im- 
age a grainy appearance. 

Figure I compares the geometries 
provided by viewing both conventional 
TV and HDTV screens from the distance 
at which scan lines arc rendered invisible. 
In a conventional system, the viewing an- 
gle is only about 10°. but an HDTV sys- 
tem provides the desired 30° viewing 
angle. 

As shown in the figure, if the number of 
scan lines is increased to 1000 or more, 
the minimum viewing distance is reduced 
to about 3 times the image height. At that 
distance a 30° viewing angle can be 
achieved. Further, due to the limited reso- 
lution of the human eye, the lines will 
blend together and give the impression of 
a smooth image. 



48 




FIG. 1— THE GEOMETRY OF TV VIEWING. With an HDTV image, a viewer can sit closer to the screen to 
attain a greater viewing angle, thereby improving the sense of realism. Because the signal has 
approximately twice as many scan lines as a conventional system, those lines are not visible at 
distances as close as three times the image height. 



Another factor adding to the impres- 
sion of realism offered by HDTV is a 
change in aspect ratio, the ratio of an 
image's width to its height. Conventional 
TV has a 4:3 aspect ratio, which means 
thiil the picture is four units wide and three 
units high. That aspect ratio was adopted 
originally lo conform to what was used at 
the time for motion-picture photography. 
These days, most films are shot using the 
Panavision process, which uses a f .85: 1 
(5.55:3) aspect ratio. It is expected that 
HDTV will use an aspect ratio between 
the two, with 1. 77: 1 (16:9) being endorsed 
by many. See Fig. 2. 

The NHK system 

As we mentioned earlier, the HDTV 
system closest to being a practical reality 
is the one proposed by Japan's NHK. That 
system uses a signal with 1125 scan lines 
and a 2:1 interlaced scan rate of 60 fields 
(30 frames) per second. NHKs HDTV 
system has already been demonstrated 
both in Japan and in the U.S. 

One problem with all HDTV systems is 
thai they potentially require enormous 
amounts of bandwidth. For instance, in 
ihe system proposed by NHK, a high- 
definition TV picture contains about live 
times more luminance (brightness) infor- 



mation that does a conventional one, thus 
requiring a bandwidth at least five times 
greater than that specified for the NTSC 
system used by U.S. broadcasters today. 
That translates to a bandwidth require- 
ment of 30 MHz, compared to the 6 MHz 
NTSC standard. 

To squeeze all of the information re- 
quired for a HDTV picture into a more 
manageable bandwidth, NHK developed 
a system called MUSE (Mt/ltiple Sub- 
Nyquist Sampling Encoding). MUSE 
converts a wideband analog studio signal 
to digital form, compressing it to slightly 
more than 8 MHz for transmission. At the 
receiver, the signal is re-expanded to its 
original form for display. The MUSE 
specifications call for: 

• Processing of luminance and chromi- 
nance information by TCI (Time Com- 
pressed /ntegration). 

• Time-compressed line -sequential pro- 
cessing of chrominance information gen- 
erating R - Y (red minus luminance) and 
B — Y (blue minus luminance) color-dif- 
ference signals. 

• Time compression of the chrominance 
signal by a factor of four. 

• Bandwidth reduction of the TCI signal 
through subsampling. 



• A PCM digital audio signal to be multi- 
plexed with the video signal. 

MUSE is known its a "motion-com- 
pensated subsampling" system. The 
terms subsampling and sub-Nyquist refer 
to the fact that when the video information 
is processed, fewer samples are extracted 
from it than would be the case if it were to 
be processed using conventional meth- 
ods, where sampling occurs at twice the 
highest frequency (i. e., the Nyquist fre- 
quency) involved; the lower sampling rate 
is the reason why that method is called 
sub-Nyquist. 

The principal trick used by the MUSE 
system is that it sub-samples the video 
signal over a four-field sequence prior to 
transmission: the sampling pattern used is 
shown in Fig. 3. That technique allows for 
the 4:1 reduction in required bandwidth. 

Reconstruction of the MUSE signal re- 
quires an HDTV receiver equipped with a 
memory capable of storing the four fields. 
For still (non-moving) parts of an image, 
the picture can be reconstructed using 
samples from all four fields since there 
will be no movement from field to field. 

But where there is movement, attempt- 




FIG. 2— ASPECT RATIOS. Here, the aspect 
ratios of conventional-TV, HDTV, and Panavi- 
sion motion -picture viewing screens are com- 
pared. 



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SUBSAMPLING POINTS: 



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□ 2nd FIELD 



I 3rd FIELD 

4th FIELD 



FIG. 3— THE SAMPLING PATTERN used by 
NHKs MUSE system. Picture information Is 
transmitted over four fields rather than the two 
of conventional TV. 



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ing reconstruction using two or more 
Melds will yield a picture with unaccepta- 
ble blurring. That's because the picture 
content will be changing from lield to 
Held, Therefore, only the information 
from one field can be used to form the 
image and a 1:4 loss of resolution occurs. 

However, a MUSE receiver also incor- 
porates a motion detector. That stage en- 
ables the receiver to integrate the 
stationary and moving pans of a scene 
into a single image. (That's where the 
"motion-compensated" part of the 
MUSE system comes in.) The result is 
that stationary parts have maximum reso- 
lution while moving parts appear slightly 
blurred. Such blurring is not considered 
serious, however, since our perception of 
sharpness is not reduced by blur in a mov- 
ing image. We simply accept it as an at- 
tribute of the motion. 

A special case in the MUSE system 
occurs when the camera is panned or 
tilted, causing the entire image to change. 
When the encoding circuitry detects that 
type of picture content, a vector represent- 
ing the motion of a scene is calculated and 
the information is sent during the vertical- 
blanking interval. At the receiver, the in- 
formation is applied to the held memo- 
ries, causing the position of the sampled 
picture elements to be shifted as appropri- 
ate to the motion. The bottom line is that 
the moving pictures are processed as if 
they were stationary ones, with conspic- 
uous blur in uniformly moving regions of 
the image held to a minimum, subject to 
the accuracy of the motion vectors. Note 
however that non- uniform moving regions 
will unavoidably suffer a loss of resolu- 
tion. In most instances, however, such 
loss will be acceptable as a consequence 
of motion. 

Other systems 

Although NHK's MUSE system is the 
one closest to implementation, work on 
HDTV is also continuing in Europe and 
the U.S. In this section we will look at 
some of the more promising systems. 

Most of these systems are based on the 
following standard: 1125 lines. 60 frames 
per second. 2:1 interlace, 16:9 aspect 
ratio. The number of lines was chosen as a 
compromise between the PAL/SECAM 
and the NTSC camps. It is more than 1000 
lines, but not exactly equal to twice either 
625 or 525 lines. Also, although 50 
frames per second is used in Europe and 
elsewhere, the NTSC standard of 60 
frames per second was accepted because it 
substantially reduces flicker and allows a 
higher sampling rate. Interlaced scan- 
ning, as opposed to a progressive scan- 
ning scheme, is used because of the 
reduced bandwidth it requires. 

Note that those specifications have not 
been formally accepted as a worldwide 
standard, however It was hoped that a 
standard would be adopted at the Interna- 



tional Radio Consultative Committee's 
1986 Plenary Assembly. Instead, a deci- 
sion was postponed until 1990, at the ear- 
liest. That postponement has added some 
confusion to the HDTV world, so there is 
no guarantee as to what shape, if any, a 
worldwide specification will take. It is 
expected, however, that the 1125/60/2:1 
standard will become a de-facto standard 
in most 60-Hz HDTV studios. 

Several of the systems are of the MAC 
(Multiplexed Analog Components) type. 
In a MAC signal, the luminance, color 
difference, and multiple digital sound sig- 
nals are compressed in time and multi- 
plexed onto the same signal. In particular. 
most European HDTV systems are based 
on some type of MAC system. 

For instance. Philips, the Dutch elec- 
tronics giant, has proposed a European 
HDTV system called HD-MAC. The sys- 
tem is based on the 625-line. 50-Hz PAL 
standard. The input signal is 1250 lines, 
50 Hz, with 2:1 interlace. Vertical filtering 
is used to make a wide-bandwidth 
625/50/2:1 signal for transmission. The 
bandwidth is reduced by transmitting 
only alternating horizontal samples: four 
fields are required to receive a complete 
HD-MAC picture. That, once again of 
course, means that the receiver must have 
a frame memory to display the 
1250/50/2:1 picture. 

Other MAC systems are similar, except 
for the numbers involved. For instance, 
B-MAC is a MAC system that's compati- 
ble with the 1 1 25/60/2: 1 proposed world- 
wide standard. 

And things have not been quiet in this 
country, either. Bell Laboratories has pro- 
posed a two-channel transmission system 
in which one channel contains an NTSC 



signal that is derived from an HDTV sig- 
nal of 1050 lines. The second channel 
contains the high-frequency luminance 
and color-difference information. Ac- 
cording to Bell Labs, a normal NTSC 
receiver would receive the NTSC channel 
with only a slight degradation of picture 
quality. An HDTV receiver would receive 
both channels and combine them using a 
frame store. The result is then scan-con- 
verted to reproduce the original 1050- line 
picture. 

CBS has proposed another two-channel 
system. One channel would contain a 
MAC-like time-multiplexed component 
signal in a 525-line/60-Hz format. The 
second channel would contain another 
time-multiplexed component signal. 
When the two signals are combined, an 
HDTV image results. The system does 
not require a receiver with frame store and 
would use Direct-Broadcast Satellite 
(DBS) delivery. 

William Glenn of the New York. In- 
stitute of Technology has proposed a sys- 
tem that makes use of the properties of 
human vision to reduce the bandwidth of 
a transmitted HDTV signal. In his pro- 
posal, an "improved" NTSC signal is 
transmitted over a standard NTSC chan- 
nel. (Those improvements could entail 
pre-combing to eliminate interference be- 
tween the luminance and color informa- 
tion, use of progressive rather than 
interleaved scan. etc. Some improve- 
ments may require modified NTSC re- 
ceiving equipment.) That signal, which 
already will offer somewhat better resolu- 
tion than standard NTSC, is accompanied 
by a 3-MHz wide auxiliary signal that 
contains high-frequency, low tempore I - 
rate information, as well as information 











NTSC 
PIXEL 


NTSC 
PIXEL 






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\ ODD FIELD 
f SCAN LINE 


NTSC 

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FIG. 4— IN THE DEL RAY HDTV SYSTEM, each NTSC pixel Is broken up into six samples for transmis- 
sion. Picture information is relayed in a sequence of six fields. 



50 



required to produce a wide aspect- ratio 
picture. The two signals would be com- 
bined in a frame store to produce an 
HDTV image. 

The Del Ray Group of Marina Del Ray, 
CA, has proposed a system that uses a 
single NTSC channel to transmit a 
525/60/2:1 HDTV signal. They propose a 
system in which a single NTSC lumi- 
nance sample (pixel) is broken up into 6 
samples. One sample is transmitted each 
field until after 6 fields the complete 
NTSC pixel is sent. The sampling pattern 
is shown in Fig. 4. At the receiver, a frame 
store is used to recreate the complete pic- 
ture. According to the Del Ray Group, 
such a signal could be displayed on a non- 
HDTV NTSC receiver with little degrada- 
tion when compared with a normal NTSC 
signal. 

A wider aspect ratio is achieved in this 
system by reducing the number of active 
video lines transmitted by 69. The Del 
Ray Group contends that due to overscan 
losses in a typical receiver, the removed 
lines would not be missed. Further, those 
69 lines could then be used to transmit 
digital sound. 

Distribution 

After an HDTV specification has been 
established and agreed upon, the problem 
remains of how to distribute material pro- 
duced in that medium to the public wait- 
ing for it. So specifications, distribution, 
and compatibility are HDTV's toughest 
remaining problems. Let's look at the dis- 
tribution problem in more detail first; later 
on we'll delve deeper into compatibility. 

As with today's video programming, 
there are two alternatives: broadcast and 
pre-recorded material. In the realm of 
broadcasting, one possibility is, of 
course, DBS. Satellites could provide a 
distribution route completely independent 
of those used for conventional broadcast- 
ing, and the compatibility issue could, in 
a sense, be skirted. It has been suggested 
that the most economical and practical 
system for distributing HDTV is by DBS 
in the 22- and 40-GHz bands. (For more 
on HDTV and DBS, see Satellite TV 
elsewhere in this issue, as well as in the 
July issue of Radio- Electronics.) 

Until recently, most observers had 
ruled out terrestrial broadcasting as a pos- 
sible distribution medium. However in a 
test conducted this past January in the 
Washington, DC area by the NAB (Na- 
tional Association of Broadcasters) and 
the MST (Association of Maximum Ser- 
vice Telecasters), two adjacent UHF 
channel slots were used to transmit a 
MUSE HDTV signal. At the same time, a 
13-GHz terres trial- microwave relay signal 
was used as a backup, and to demonstrate 
the feasibility of using that band in areas 
where sufficient UHF spectrum was un- 
available. On the UHF band the broadcast 
was made using vestigial sideband AM; 




FIG. 5— AN HDTV videotape recorder from Sony 
was used this past spring to present one de- 
signer's spring line in New York. 



on 13 GHz, FM was used. In general, the 
results were satisfactory, although some 
problems were encountered with the PCM 
digital audio, which was designed for sat- 
ellite rather than terrestrial distribution, 
when the signal was attenuated. That 
problem will have to be solved to make 
terrestrial distribution of a MUSE signal 
practical. 

The other way in which HDTV pro- 
gramming could be provided is in pre- 
recorded form — on videotape and vid- 
eodiscs. While the wide band widths of 
HDTV are beyond the capabilities of con- 
ventional broadcast and consumer equip- 
ment, Sony and other manufacturers have 
developed systems capable of storing 
HDTV images. See Fig. 5. 

Compatibility 

High-definition television is certainly 
practical. Indeed, it already exists. The 
problem that concerns many, though, is 
how to get program material produced in 
that medium to the greatest number of 
viewers. 

In the past, virtually all improvements 
in broadcasting in the U.S. have been 
achieved within the framework of the sys- 
tem established in the 1940's by the 
NTSC; other TV systems have also main- 
tained compatibility with existing equip- 
ment as they were improved. Although 
newer receiving equipment has been re- 
quired to take full advantage of improve- 
ments such as color and stereophonic 
broadcasts, program material incorporat- 
ing those improvements has generally 
been able to be received and enjoyed using 
equipment already in use. 

The ideal, of course, is to develop a 
system in which a current receiver could 
accept an HDTV transmission and display 
it in HDTV form. In all likelihood, that is 
an unattainable dream. More likely would 
be a system in which an NTSC receiver 
would be able to receive an HDTV signal 
and display it with the same or slightly 
worse quality as it displays an NTSC sig- 
nal. Another possibility would be a sys- 



tem in which an NTSC receiver could be 
modified, perhaps through an outboard 
adapter, to receive HDTV signals. Of 
course, the cost of such a modification 
must he relativelylow to be practical. If it 
is too high, most consumers would opt to 
forgo modification and simply replace 
their equipment when they decide to up- 
grade. A final possibility would be that an 
NTSC receiver simply could not be used 
to receive and display HDTV signals in 
any form. In other words, it would be a 
completely incompatible system. 

Of course, compatibility is a desirable 
goal, but you can not overlook the cost at 
which it is achieved. At this point in 
HDTV research, it appears that the higher 
the compatibility with existing systems, 
the poorer the high-definition perfor- 
mance. Images will be strikingly better 
than those provided by a non-HDTV sys- 
tem, but they will not provide maximum 
possible performance. 

On the other hand . the highest perfor- 
mance HDTV system will likely be 
achieved only if the compatibility prob- 
lem is completely ignored. In that event, a 
separate programming distribution sys- 
tem likely will develop that will supply 
programming to viewers that possess the 
appropriate equipment. 

Ignoring compatibility altogether is not 
without precedent. When FM radio 
broadcasting was introduced, that mode 
was incompatible with the existing AM 
system. That, however, did not stop peo- 
ple from investing in what then was ex- 
pensive equipment to take full advantage 
of the benefits (superior audio quality) 
offered by that medium. 

The newer FM system coexisted with 
the older AM one. and prospered. Today, 
it is commonplace to find AM and FM 
tuners in the same piece of equipment — - 
even small portable receivers. And even 
now the same program material is some- 
times broadcast by a station in both AM 
and FM, so that those with FM equipment 
can enjoy the all the benefits of the new 
technology, and those who are still AM- 
bound will not be left out. 

Similarly, television broadcasters could 
provide high-quality HDTV program- 
ming by satellite or some other means to 
those equipped to receive it, while per- 
forming scan- and media-conversion at 
their own facilities and simultaneously 
sending NTSC- formal signals containing 
the same material on their conventional 
VHF and UHF frequencies for viewers 
with existing NTSC (or PAL or SECAM) 
receivers. 

Whatever final form politics, policies, 
and technology dictate for HDTV, it ap- 
pears that there's no holding that tech- 
nology back. In just a few short years, 
Japanese viewers will be enjoying its ben- 
efits; it's very likely that shortly thereafter 
we'll be getting the "big picture" in this 
country, too! R-E 



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51 





mm. 



LVI.N INK) l"Hh liAKI.Y Yl-.AKS OJ" SOUl> 

statc equipment design, the FCC's exam- 
ination lor a 1st Class General Radio- 
telephone License which is almost 
universally known as a "First-Phone." 
covered most of what there was to know 
about the electronics of communications. 
Except for radar, which was an endorse- 
ment on the license obtained through a 
separate examination, the knowledge 
needed to gel a First-Phone was so broad 
and so thorough that the license was often 
a prerequisite for general technical em- 
ployment, even though the license was 
intended only for technicians whose job 
involved transmitter adjustments. 

The reason why employers placed so 
much faith in the First-Phone was because 
it certified a minimum level of knowledge 
and skill. Even if the job open was repair- 
ing home stereo receivers, an employer 
could be reasonably certain that someone 
with a First- Phone had an acceptable un- 
derstanding of both electronics and elec- 
tric fundamentals. 

But suddenly, almost overnight, the 
general radiotelephone license lost both 
its value and its need. First, as with all 
other things, electronics technology be- 
came so complex and sophisticated that 
no one could be expected to be expert, or 
even merely competent, in more than one 
or two specialized areas of interest. Be- 
cause the radio broadcasting services no 
longer represented a major area of elec- 
tronics, having a license that certified 
competence with transmitters and anten- 
nas no longer implied competence with 
the mainstream of electronics equipment. 

Second, there was something called 
"license deregulation." Modem tech- 
nology had made the stability of radio 
equipment so reliable that as far as the 
FCC was concerned, other than for the 
ship and aircraft services there was really 
no longer a need for a specially-licensed 
technician. So the FCC eliminated the 
requirement that only an FCC-licensed 
technician could make adjustments and 
repairs to transmitters: It became the re- 
sponsibility of the owners and operators 
of radio-transmitting equipment to ensure 
proper operation. (Although Congress 
implied that the FCC could recognize 
technician "certification" by industry- 
sponsored private organizations — and 
that agency has sent out notices about 
programs available — it officially recog- 
nizes no "private" certification of any 
kind.) 

Since an FCC license no longer re- 
llected the major interests of electronics, 
und since very few positions in the com- 
munications industry required an FCC li- 
cense, how, then, was an employer to 
evaluate a potential employee's technical 
know led tie and skill? 



CERTIFICATION 
FOR 




ELECTRONICS 
TECHNICIANS 

If you really have specialized knowledge and skills- 
11 you know your stuff— you can become a 
certified electronics technician. 

W. CLEM SMALL GET 



For the seasoned technician, past em- 
ployment records may be ail the recom- 
mendation that's needed, but for the less 
experienced person it is usually a different 
and more complex situation. While it is 
possible for an employer to ask for tran- 
scripts of the applicant's trade-school 
training, many new technicians who want 
to work in communications have picked 
up their knowledge without going to a 
formal trade school: How are they to es- 
tablish their knowledge and competence? 

Certifications 

Often, employers will test job appli- 
cants, but if properly done, on-site testing 
can be a relatively expensive undertaking 
that often costs more than many small 



shops can afford to spend. One effective 
way to ensure the proper testing and eval- 
uation of potential employees is to use the 
certification procedures of the various 
professional organizations that have 
evolved to serve the communications and 
electronics industry. In fact, within the 
broadcast and telecommunications indus- 
try, most employers who formerly re- 
quired the FCC First-Phone now require 
(or accept) certification by a professional 
or industry-sponsored organization. 

The exact procedure used for the cer- 
tification of technicians depends on the 
particular organization. For example, one 
early approach was to consider a techni- 
cian's past FCC license level and perhaps 
his employment under that license. Both 



52 







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'///orr/////f,j/£,/ 



FIRST CLASS 

• G* -sr.il Rfcrfiat ■ 1 1 p h G ft* C» rli flCR.1 *.• 



I Motm I m*tn 



MtM 



ftATC «' - 1 •- - ■■ ■ 



IS A UCEH5ED RADIO OPERATOR, iUfHOIHIte, SUBJECT TO ART SPECIAL ENDORSE W(N I PLACED NEREO*. TO 4P[ ■ « TC THE CUSSES OF 

LICENSED RADIO STATIONS fOR WHHlN THIS. CLASS OF LICENSE IS VALID UNDER THl ORDERS. tULIS J.*0 REGULATIONS OF THE FEDERAL 
COHHUNICAITONS COMMISSION. ANT STATUTE OF THE UNITED STATES AND AH* TMATT 10 WHICH THE UHJTED STATES 14 A rxWft. 

THIS LICENSE IS GRANTED UNDER THE AOTKDRI rF DF THE CCHHUFHCATICKS ACT OF ISJi, AS AM1H&ED. »"3 THE lERKS AND EQUDlTIONS 
THEREOF AND OF ALL LEGISLATIVE ACTS, EXECUTIVE ORDERS, *»Z TREATIES TO WHICH THE UNITED STATES IS SlGflATOKT, AHEr ALL OiDEftS, 
tULIS AMD B ECU | AT ION E OF THE FEDERAL COMMUNICATIONS COMMISSION, WHICH ARE BINDING UPON NA&IO OPERATORS, ARE HADE A PART 

hueot *s THoysn sh-cut-cally srr out in full herein, 

*FITNE» THIf 1FCEHSE NOR THE RIGHTS CE (111 TIES TQ< HEREIN i.H*LL RE ASSIGNED OH OTHERWISE Tr?ANSf EITREQ '0 AHT -OTHER PlRSON. 



?«bni*rr 2Z. 197B 



RLACE *NO DATE Of IHLiAHGEi i«B fTKlClRCq, California 

DATE AHO TIME OF EH »IH A 1 IDH= f^bniRXy 52, 1933 jh.T T«REE O'CLOCK A.H..,, EASTERN IT 



SPECIAL EM &ORSEM EH T 




iatulif OJjrCW 



EXPIRED 




NOT VALID UNTIL SIGNED 



THIS WAS THE LEGENDARY First-Phone FCC license. Ho longer in existence, it attested to the 
holder's general technical competence. It was often a "ticket to success" in communications. 



' V V v V'V V V V w V V ^ u V V u V V W V V V- >■ 



/fit fat tiff fw aw/ f/hcre/y o/ 

BEGIST£ftEO RADIOTELEPHONE OpEHATOR LICENSE 

[GvArf»l HtfO M h u riOni Cv jitacawl 

Thrr cirtifiti Ltiit the individual Fumtct intf oncjsbrd bt^ow ii i licensed radio operator a--d Is juthofpied eg opeta^e 

llctnud radiQ LUKDM for VrtliCh> llnS et«i Of llcenie li valid The #Uth«llY qraillc<! .1 lubptct 10 any tndVHTnrn.1 

plACtd on trull licnrtK:. Thi auihof iiy g/antld ii i>» subject to Irvf wdors, rul« r md regulations 01 tht interftitionftJ 

Society of C»r1iFiKf ELKlTOFIJCI Technician! Rftd the EtllUUS ■ iha UoltBd StllM. 

The lltftiie may not be Ksigntd or iranifrrred to my QtliK oflnoo. It expirn it thfH o'clock AM EHtefn Sundard 
Tlnn« on Ihit dm* shown tw^aw. 



SVC 


HC^I 


WfliDhT 


Color Eyas 


ColChT ha.i 


Dji* of Birth 


PIkh dI I«wjom 


Expifi!!on Dau 


Lpcchh Numbec 



ifiify 



He! W<4 Without tKET 5iK 



SEVERAL PHIVATE CERTIFICATES are similar in appearance or format to the old FCC First-Phone 
license. 



the A/ational Association of /Justness And 
Educational fladio (NABER) and ihe So- 
ciety of Broadcast Engineers (SBE) have 
had certification programs that required 
prior possession of an FCC license as a 
basic requirement. Upon satisfaction of 
their requirements, a certificate that re- 
sembles the old FCC license is awarded to 
the applicant. On the other hand, various 
aspects of existing and emerging radio 



technologies such as cellular telephone, 
as well as the telecommunications skills 
needed since the breakup (deregulation) 
of AT&T, requires highly specialized 
knowledge, which is certified through 
special exams given by the National Asso- 
ciation of /?adio And Telecommunication 
Engineers (NARTE), which certifies on 
two levels: technician and engineer. Al- 
most without exception, NARTE cer- 



tification requires a combination of ad- 
vanced schooling and extensive experi- 
ence. For example, their lowest class of 
engineering certification requires either a 
two- or four-year engineering degree, or 
previous high-level technical certification 
plus two years of engineer-level experi- 
ence. The NARTE s minimum technician 
certification (Class IV) requires an exam- 
ination, while the highest (Class t) re- 
quires previous certification plus six years 
verifiable radio or telecommunications 
experience. 

CET 

Long before FCC deregulation, elec- 
tronics professionals recognized the need 
for certifying electronics technicians in 
troubleshooting consumer products, in 
basic logic circuits and industrial con- 
trols, and the safety and accuracy of cal- 
ibration for medical electronic instru- 
ments. As early as 1 965. the CET test 
used by the international Society of Cer- 
tified Electronics Technicians (ISCET) 
used exams that tested black and white 
television adjustments, audio speaker en- 
closures and adjustments, and the use of 
electronics test equipment. Nearly 
20,000 technicians had passed those 
exams (out of about 70,000} even before 
the FCC deregulation. Persons passing 
the appropriate tests may first attain the 
apprentice electronics-technician certifi- 
cate, and then one or more advanced jour- 
neyman-level certificates. 



CERTIFICATION PROGRAMS 

Electrortic's Technicians 
Association 

604 N, Jackson St. 
Greencastle, IN 46135 

International Society of 
Certified Electronics Technicians 
2708 West Berry St. 
Fort Worth, TX 76109 

National Association of Business and 
Educational Radio 
P.O. Box 19164 
Washington, DC 20036 

National Association of Radio and 
Telecommunications Engineers 
P.O. Box 15029 
Salem, OR 97309 

National Institute for Certification in 
Engineering Technologies 
1420 King St. 
Alexandria, VA 22314 

Society of Broadcast Engineers 
P.O. Box 50844 
Indianapolis, IN 46250 



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53 



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E 



Two organizations lhat offer a CET or 
C.E.T. testing program are ISCET and the 
Electronic Technician's Association 

(ETA). Options that are available from 
one or the other of these programs include 
most major areas within electronics tech- 
nology. 

Within the ETA program are the ad- 
vanced options of Senior C.E.T and Mas- 
ter C.E.T., which are available to persons 
with eight or more years of experience in 
die profession. Higher passing scores in a 
chosen option are required for the senior 
level than for the lower levels. The master 
option requires passing an examination 
that covers consumer electronics, com- 
mercial electronics, communications, in- 
dustrial electronics, computers, and bio- 
medical electronics. 

ISCET has two levels of certification. 
Associate C£T*s must pass an exam cover- 
ing basic electronics, circuits, semicon- 
ductors, test instruments, and basic 
troubleshooting. Technicians with four 
years experience can take the higher-level 
Journeyman exam at the same lime. They 
must be certified at the Journeyman level 
to use CET after their names. CET's are 
issued permanent certificates suitable tor 
framing and a plastic wallet card. 

Once certified as a CET or C.E.T., 
technicians arc eligible For membership in 
the parent organization, ISCET or ETA. 
Members receive books, magazines, re- 
prints, and regular technical material; 
may attend conventions and technical 
training programs; and receive discounts 
on books, tapes, and software. But the 
real benefit of certification is a growing 
awareness within the electronics industry 
that a certified technician is a person who 
has demonstrated considerable skill, un- 
derstanding, and competence in his or her 
tested areas. 

The FCC and CET 

The FCC has made no official sanction 
of any private-industry certification pro- 
gram. Public notices have been issued by 
the FCC to assist technicians in locating 
certification programs, but those have 
specifically stated. "The Commission 
does not approve, endorse, or officially 
sanction any private sector certification 
program..." However, in its Report and 
Order, docket 83-322. 49 Fed. Reg, 
20658, the Commission did endorse the 
concept of private sector certification pro- 
grams as a possible substitute for Com- 
mission testing of commercial radio 
operators. 

The right certification 

It is reasonable to expect that, as more 
and more jobs require certification of 
some kind in lieu of the old First-Phone, 
we're bound to sec a plethora of private 
organizations offering their own version 
of private licensing. Bear in mind that 
certification that isn't specifically recog- 



PKKSIUtNT. NAUEK 




AUGUST 1. 1984 




The National Association of 

Business and Educational Radio, Inc. 

Certifies that 



has demonstrated a knowledge of Ihe Federal Communications Commission's Rules and Regulations 
governing ihe Land Mobile and Private Fixed Radio Services and has shown a general comprehension 
of the theories of electronics and radio propagation. This individual is hereby recognized as a NABElK 
Certified Technician through a FEDERAL COMMUNICATIONS COMMISSION endorsed program. 



EVEN WHEN THEY DON'T RESEMBLE the First-Phone license, some private certificates such as 
this one state or imply endorsement by the FCC, although the FCC does not approve, sanction, or 
endorse any private program. 



International Society of 
Certified Electronics Technicians 

Associate Certified Electronics Technician 



be it known by these presents lhat 
p, ; .:v ... - 

thtti:: L-i. 



has succotsiuliy compiasid me Technical Tests and Ftequii ements g«,ng univeisal recognition tDf 
competence ability and knowledge as an Associate CeMitrtO Eleclionics Technician 



fills ceMiticnFe is ss'jed |Oin1ky by 



ILBtJUlli* Lie* 



vJI'lii...' Li, 



PRIVATE-SECTOR CERTIFICATION attesting to a minimum level of knowledge and skill ts available 
for various areas of electronics. It often serves as a "ticket to success." 



nized by employers is worthless. If you 
want a particular kind of job. say in cel- 
lular phone, or even broadcasting, check 
with some large operations and specifical- 
ly ask if they recognize or require private 
certification or licensing and, if so. from 
whom. If you choose to work in an area 
that requires private certification, bear in 
mind that as a general rule the higher the 
certificate for which you qualify, the 
greater the potential job opportunities. 



For more information on how to get 
certified in various electronic tech- 
nologies, you should contact the major 
private certification organizations listed in 
the box that can be found elsewhere in this 
article. Although those organizations are 
not-for-profit, they do have a reasonable 
fee for testing and processing. In par- 
ticular, we suggest you enquire as to what 
study guides they specifically recom- 
mend R-E 



54 




D 




'21 



C~Z3 




TRANSISTOR 



WE WERE HAVING TROUBLE FINDING AN 

exact replacement transistor while repair- 
ing a piece of equipment recently. Figur- 
ing thai an exact replacement was going to 
be impossible to hnd. wc began to discuss 
what to do. And someone pointed out that 
there were only two kinds of bipolar tran- 
sistors — NPN and PNP. Of course, values 
for various characteristics vary widely, 
even for a specific transistor; but in many 
circuits, a garden -variety device will work 
(and did in our case). 

Designing and repairing transistorized 
circuits is much simpler than you might 
suspect. A well-designed circuit has built- 
in tolerance, so it's probably not device- 
sensitive. The most important charac- 
teristics to consider when substituting de- 
vices or designing a circuit from scratch 
are operating frequency and power level. 

What follows is the design procedure 
we went through to solve an audio-gain 
problem. Try it when you need a little 
extra gain for that next audio project. 

An audio amp 

This particular project involved inject- 
ing the audio from a TV receiver into a 
stereo system. The audio-output portion 
of the TV-audio receiver was abandoned 
because of its poor frequency response 
and high distortion. Instead, we wanted to 
come right off the detector into a quality 
audio amplifier and speaker. So. after 
picking off the audio at a convenient point 
in the set (in this case, from a potentiome- 
ter), wc wanted to feed it to the auxiliary 
input of the stereo amplifier. 

The amplifier we used required an input 
of I volt rms, but a quick check with an 
AC VTVM indicated that our picked-off 
audio signal was only 0.1-volt rms. Ob- 
viously, an amplifier with again of 10 was 
needed. 

Scanning the literature on transistor 
amplifiers revealed that a common-emit- 
ter amplifier with a voltage-divider bias 
circuit would solve our problem nicely. 
Such a circuit is shown in Fig. 1 . Some of 
that circuit's characteristics include: mod- 
erate input impedance, moderate voltage 
gain, inverted output, and input/output 
impedance and gain that depend only 
slightly on transistor beta. 

There are, of course, several rules that 
must be followed in using a common- 
emitter amplifier, including: 

• With a positive supply use an NPN 
transistor. 

• With a negative supply use a PNP tran- 
sistor. 

• The supply voltage must not exceed the 
transistor's V CE rating. 




AMPLIFIER 
DESIGN 

JACK CUNKELMAN 

It's easy to design a simple transistor amplifier, Here's how. 



• The power-dissipation rating of the 
transistor must not be exceeded. 

• The beta of the transistor should be 100 
or higher. 

In our example the following facts are 
known: 

• Our amplifier had a single-ended 12- 
volt power supply. 

• We need a voltage gain of 10. 

• The input impedance of the amplifier 
should be about 15K, the same as the 
potentiometer from which audio was 
taken. 

• Th e i mpedance of the ste re o am p I i he r 's 
auxiliary input is about 50K. 

As is the case in most circuit designs, a 
few facts are known, and the rest must be 
calculated or picked using a few "rules of 



thumb." We will learn how to make the 
calculations next. 

Doing the math 

For maximum undistorted output 
swing, we will make the quiescent collec- 
tor voltage 'A the supply voltage. See Fig, 
2. The drop across R c must therefore be 6 
volts. 

The value of R c , the collector load re- 
sistance, is chosen considering output im- 
pedance, gain, and collector current. If 
possible, the output impedance should be 
lower than the impedance of the circuit wc 
are feeding by a factor of 10 or more. 
Doing so will avoid circuit loading. So 
let's make R c equal to 4700 ohms, which 
is about 50K/10. 



> 

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LISTING 1 

10 CLS TO THIS IS";R1 

20 REM TRANSISTOR AMPLIFIER CALCULATIONS 360 PRINT "CALCULATION OF THE INPUT AND 

30 REM BY JACK CUNKELMAN OUTPUT CAPACITOR VALUES" 

40 REM APRIL 19B6 370 INPUT "LOWEST FREQUENCY THIS AMP SHO 

50 GOSUB 900 ULD PASS"jF 

60 INPUT "SUPPLY VOLTAGE" ;V 3B0 CI = 1/(3.2*F*IZ) 

70 PRINT "THE DROP ACROSS THE COLLECTOR 390 CI = CI * 1E+6 

RESISTOR ="V/2"V0LTS" 400 C2 = 1/C3.2*20*Z) 

SO INPUT "INPUT IMPEDANCE OF THE FOLLOW I 405 C2 = C2 * 1E+6 

NG STAGE(OHMS) ";Z 410 IE = VE/RE i RJ ■ .03/IE 

90 RC = Z/10 420 A - RC/RJ 

100 PRINT "COLLECTOR RESISTOR, f?C SHOULD 430 C3 - 1/<6.2*F*RJ> 

BE "RC" OHMS" 440 C3 - C3 * 1E+6 

105 INPUT "THE CLDSEST 5*/. RESISTOR VALUE 500 CLS 

TO THIS IS"jRC 510 PRINT "PARAMETERS FOR A COMMON EMITT 

110 IC - (.5*V)/RC ER AMPLIFIER STAGE" 

120 PRINT "THE COLLECTOR CURRENT IS"IC * 520 PRINT 

1000"MA" 530 PRINT "SUPPLY VOLTAGE ... 

130 INPUT "DESIRED VOLTAGE GAIN"}G . "V" VOLTS" 

140 RE = RC /G iR* ■ CHR*<32) 540 PRINT "COLLECTOR RESISTOR (RC) 

150 PRINT "THE EMITTER RESISTOR FOR THIS . "RC'OHMS" 

GAIN IS "RE "OHMS" 550 PRINT "EMITTER RESISTOR <RE> .... 

160 IF RE<=39 OR RE =>100i THEN 170 ELSE . "RE "OHMS "R* 

ISO 560 PRINT "BIAS RESISTOR <R1> 

170 R* - CHRSC42) ."R1"0HMS" 

ISO INPUT "GERMANIUM (G) OR SILICONE (8! 570 PRINT "BIAS RESISTOR <R2) 

TRANSISTOR TYPE"sT* ,"R2"0HMS" 

190 IF T* »"G" THEN 210 5B0 PRINT "INPUT CAPACITOR (CI ) 

200 IF T* ="S" THEN 220 ELSE ISO ."C1"MF" 

210 J = .2 :GOTO 230 590 PRINT "OUTPUT CAPACITOR (C2) . . . . 

220 J - .6 . "C2"MF" 

230 VE = IC * RE 600 PRINT "VOLTAGE GAIN 

240 PRINT "THE DROP ACROSS THE EMITTER R . "G 

ESISTOR IS"VE"VOLTS" 610 PRINT "TRANSISTOR BETA 

250 VB » VE + J . "B 

260 PRINT "THE BASE VOLTAGE MUST BE"VB"V 620 PRINT "LOW FREQUENCY LIMIT 

QLTS" ."F"HZ" 

270 INPUT "WHAT IS THE DESIRED INPUT IMP 630 PRINT "EMITTER BYPASS - "C3"MF FOR A 

EDANCE FOR THIS STAGE"; IZ GAIN OF "A 

230 R2 = IZ*RE*100/< <RE*100)-IZ> 700 INPUT "RUN AGAIN.. Y OR N";R* 

290 PRINT "THE BIAS RESISTOR, R2 IS"R2"0 710 IF R* ="Y" THEN 10 

HMS" 720 IF R* = "N" THEN END ELSE 700 

300 INPUT "THE CLOSEST 5% RESISTOR VALUE 900 PRINT "CALCULATIONS FDR A COMMON EMI 

TO THIS IS";R2 TTER AMPLIFIER STAGE" 

310 VD = V - VB : 12 = VB / R2 910 PRINT 

320 IB - IC/B 1000 INPUT "TRANSISTOR BETA IF KNOWN (0 

330 Rl = <V - VB1/CIB + 12) . IF UNKNOWN)" ;B 

340 PRINT "THE BIAS RESISTOR, Rl IS"R1"D 1010 IF B = THEN B = 100 

HMS" 1020 RETURN 
350 INPUT "THE CLOSEST 57. RESISTOR VALUE 



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DC 



Collector current. I c , is equal to 0.5 
V cx VR r . or 6/4700 = 1.28 mA. That 
current is certainly low enough that we 
will not exceed any collector-current rat- 
ings, so let's go on. 

To achieve maximum stability, the 
emitter resistor should be in the range of 
40 to 1000 ohms. Voltage gain (A v ) = 
R ( ./R, : . so R [; = R c -/A v In our case R,. 
equals 4700/10. or 470 ohms. That falls 
within the range of acceptable values. 

The current through the emitter resistor 
consists of the collector current plus the 
base current. The base current here is sig- 
nificantly smaller than the collector cur- 
rent, so it can be ignored for the next 
calculation. 



The voltage drop across the emitter re- 
sistor = I c X R E , or 1.28 mA X 470 
ohms = 0.602 volts. The base voltage 
must exceed the emitter voltage by 0.6 
volts for a silicon transistor and by 0.2 
volts for a germanium transistor. We'll 
use a silicon transistor in our circuit, so 
the base voltage must be 0.6 -I- 0,602 = 
1.202 volts. 

The input impedance of the circuit 
equals R2 in parallel with the emitter re- 
sistor times beta: input impedance will 
vary with the transistor's beta. For our 
example, assume we are using a transistor 
with a beta of 100. We want the input 
impedance to be about 15000 ohms. Solv- 
ing for R2. we find: 



Z, N = (R2 x R e x p)/[R2 + {Re x p)] 

R2 = (Z, N x R E x (J)/[(R E xp)- Z IN ] 

R2 = (15000 x 470 X 100)/[(470 x 100) 
- 15000] 

R2 = 22,030 ohms 

We can use a 22K resistor. In general , if 
input impedance is not critical , for max- 
imum stability R2 can be 10 to 20 times 
R E . 

The drop across R2 must be 1.20 volts, 
so the current through R2 is 1.20/22,000, 
or 0.054 mA. Therefore. Rl must drop the 
rest of the supply voltage, which is 12 — 
1.20 = 10.8 volts. "The current flowing 
continued on page 77 



56 




ROBOT 



The robot's command language 



Part 9 



now that we ve As- 
sembled the robot's 
hardware, it's lime to dig into the soft- 
ware. In this article we'll describe the R-E 
Robot's command language, RCL 
(Robotic Control Language). It's an easy- 
to-learn and easy-to-use language written 
in FORTH. Don't be scared by FORTH; 
you can use RCL without being an expert 
at programming in the language. And, as 
you leam RCL, you'll leam (painlessly) 
the basics of how FORTH works, so that, 
if you want to, you can go on and learn the 
language itself. To give you a chance to 
see RCL in action, we'll present a robot- 
based mail-delivery system. You can 
study our program to learn how RCL 
works, and you can also use it as the basis 
of your own program. 

How difficult is RCL? Not very. For 
example, suppose you wanted the robot to 
move in the forward direction 3 .4 feet at a 
speed of 2 miles per hour. You would 
simply type in the following code: 

RERB 2 MPH 3.4 FEET FORWARD 

RCL includes commands to move the 
robot forward and backward, to turn left 
and right, to move its manipulator up and 
down, and to open and close a gripper. 



You can combine a sequence of com- 
mands and store them for execution at a 
later time. In addition, commands can 
also be executed immediately from the 
keyboard. 

Real-time control 

The R-E Robot consists of a computer- 
controlled set of electromechanical de- 
vices. The assembly is broadly known as a 
motion-control system . 

Real-time motion control requires real- 
time sensing and processing. One way to 
ensure proper sensing and processing is to 
force the computer to execute a control 
loop at regular intervals. That control loop 
will be the computer's highest priority. 
Everything else the computer does will be 
secondary, and it will have to do those 
other things as it finds time. 

A simple way to implement the control 
loop is to have a clock IC generate an 
interrupt at regular intervals. Each time 
the clock interrupts the microprocessor, it 
will execute the control loop, and then it 
will return to whatever it was doing before 
the interrupt occurred. The amount of 
time the computer spends executing the 
control loop must be less than the time 
interval between interrupts. 



RCL basics 

The software that controls the robot is 
built up layer by layer. The most primitive 
words must be defined first; more -com- 
plex words are defined using the pre- 
viously defined words; at the top level are 
the RCL words that make motion control 
easy. As each word is defined it can be 
tested and debugged. When it is debug- 
ged, the next layer may be defined. 

Notice that you are defining words, 
rather than writing a program, as with 
most computer languages. That's not just 
a matter of semantics; it's also a way of 
looking at a programming problem. The 
problem can be broken down into a series 
of smaller problems, and then those prob- 
lems can be broken down further, and so 
on, until you have a set of problems that 
can be programmed. Each little problem 
becomes a FORTH word, which in turn 
becomes part of another FORTH word, so 
that eventually all we have to do is say 
something like 

TURN-LEFT 

The real-time control portion of RCL 
consists of the hardware interface, inter- 
rupt control, following-error monitoring, 
velocity control, and position control. 



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Low- 1 eve I words 

The most-primitive words deal with the 
robot's hardware: turning the motors on 
and off, setting the direction in which 
each motor rotates, and enabling the 
speed-control circuits. To eonlrol the 
hardware, values must be written to and 
icad from various registers on the robot's 
control board. Those registers are read 
and written using the microprocessor's 1/ 
O statements (IN and OUT). In RCL, to 
write an eight-bit value to an output port, 
the word PC ! is used: 

PC! (value port — -) 

That statement specifies thai value is to be 
output to I/O port part. A word about 
notation is in order. The stack diagram, 
enclosed in parentheses, represents the 
parameters required by the word PC! In- 
put parameters appear to the to the left of 
the dashes, and output parameters appear 
to the right. In this case there are no output 
parameters. 

FORTH words in general (and those of 
RCL in particular) make extensive use of 
the stack, both for parameters supplied to 
a word, and those that it may produce. The 
lop of the stack is always the parameter 
furthest to the right. In the preceding ex- 
ample, the slack diagram shows that the 
value to be written must be pushed on the 
stack followed by the port to which it is to 
be written. The word PC! removes these 
parameters from the stack, uses them, and 
leaves nothing on the stack. Other words 
may leave one or more values on the stack . 

Motor-control words 

Several words operate the speed-con- 
trol circuits and the relays. For example, 
ENABLE and DISABLE write an appro- 
priate value to turn on or off a particular 
function of the hardware. STOP-LEFT, 
STOP-RIGHT, and STOP use DISABLE 
to turn the relays off. FORWARD, RE- 
VERSE. CW, and CCW enable the proper 
relays to allow the motors to turn in the 
desired direction. CW and CCW allow 
turns to be made by enabling the wheels to 
turn opposite to each other. GO and 
COAST enable and disable the speed- 
control circuits and the motor-drive cur- 
rent as well. 

Speed control 

Hardware on the control board is re- 
sponsible for controlling speed (accelerat- 
ing and decelerating). The hardware 
makes the software system much simpler 
than it would be if the software were re- 
quired to maintain speed alone. The 
phase-locked loop on the control board 
maintains the desired motor speed under 
varying loads. The software only has to set 
the speed, and to accelerate and decele- 
rate the base unit. 

The speed at which each motor runs is 
determined by the frequency of a signal 
that is generated by counter of the 8253 



timers. Setting the number of counts in 
the counter determines the period of a 
squarewave output. The phase- locked 
loop circuitry responds to the frequency 
corresponding to that period. 

The frequency of the signal applied to 
the 8253 's on the motor-control board is 
the 2-MHz system clock divided by 16, or 
125 kHz. Therefore a count is generated 
every 8 microseconds (1/125,000). The 
8253 is programmed to generate a square- 
wave whose period corresponds to the val- 
ue loaded into the counter. So, if the 
counter is loaded with the value 125, the 
total period would be 125 x 8 microse- 
conds, or I millisecond, which corre- 
sponds to a frequency of 1000 Hz. 

With a 500-count-per-revoIution en- 
coder, the motor speed would be 1000/500 
= 2 revolutions per second, or 120 rpm. 

The counter can be loaded with any 
value between 1 and 65 ,536 (0 actually), 
corresponding to frequencies ranging 
from 125 kHz to just under 2 Hz. 

Interrupt control 

Motor speed must be updated many 
times per second to produce smooth ac- 
celeration and deceleration. The update 
rate is set by the interrupt-control routines 
to 100 times per second (i. e., there are 10 
ms between interrupts). The 80188 micro- 
processor has three built-in timers that can 
generate interrupts. Timer is used by the 
BIOS and the DOS to maintain a time-of- 
day clock. The BIOS is set up to generate 
interrupt OlCh every time timer counts 
down to 0. If we change the count value in 
timer we can use it to generate the 
motor-control interrupt. However, the 
time-of-day clock will count in 10-millise- 
cond periods instead of the usual 55-milli- 
second periods, so a set of time-of-day 
words will have to be defined for the new 
rate. In addition, we'll have to install a 
new BIOS-level interrupt handler to main- 
tain compatibility with MS-DOS. 

First of all, we must define the interrupt 
routine we want to execute. Then we can 
install that routine so that it is executed 
each time the interrupt is generated by the 
timer. 

The word 1NT-OFF disables interrupt 
generation by the timer so that we can 
change the interrupt vector, or disable it. 
INT-ON turns timer- interrupt generation 
back on. SET-TIMER takes a count that 
sets the period for the timer. The input 
frequency to the timer is 2 MHz/3, yield- 
ing a period of 1.5 microseconds per 
count. If the count is set to 6667, the timer 
will countdown to every 10 milliseconds 
and generate an interrupt. 

GET — CS is a special word that is used 
to return the code segment in which the 
FORTH system is executing. SET-INT 
sets the interrupt vector to the word we 
want to execute each time the interrupt is 
generated. 

INSTALL performs all the tasks neces- 



SOFTWARE SOURCES 

Micro K Systems (15874 East Hamilton 
Place, Aurora, CO 80013. 303-693-3413) 
will provide the following: Commented 
source code in RE-robot disk format, 
$2.00. Printed source-code listing, 
$15.00. Two 27128 EPROM's with source 
screens (and without comments) for the 
RE Robot, $39.00. With EPROM's you 
won't need a disk drive, but you should 
also obtain the printed listing to read the 
comments. The Laxen and Perry F83 
Model disk with full source code and met- 
acompiler for customizing F83, in MS- 
DOS 360K format, for a PC compatible 
computer, $25.00. (Very useful for learn- 
ing FORTH if you already have a PC.) All 
orders must be prepaid. NO COD's. In- 
clude $3.00 for shipping with each order. 
Additional source code and applications 
will be available from Micro K Systems. 
Contact them for more information. 



sary to link a new interrupt handler into 
the microprocessor's interrupt vector in 
low RAM. After executing INSTALL the 
interrupt-control word will be executed 
every 10 milliseconds, and will continue 
to do so until the system is turned off, the 
interrupt is disabled, or a new interrupt 
routine is installed. 

Position-counter words 

The hardware position counters must 
be initialized by the robot's software. In 
addition, the position counters are only 16 
bits wide, so the robot won't move very 
far before the counters overflow. So it's 
necessary to extend counter length with 
software. If we look at the counters often 
enough, they will not overflow. The soft- 
ware maintains a 32-bit position counter. 

Because the counter routines must be 
executed many times per second, the time 
required to execute those routines is im- 
portant. So all counter routines (and sever- 
al others) have been written as CODE 
words. To experiment with those words, 
you'll have to know 80188 assembly-lan- 
guage programming. 

The high-level words for reading the 
counters are ?CNTl and ?CNT2 to read 
the positions of motor 1 and motor 2, 
respectively. The hardware causes the 16- 
bit counters in the 8253 IC's to decrement 
for each encoder count that is in the proper 
direction. The difference between a 
motor's forward and reverse counts gives 
the absolute position of the motor. 

Following-error words 

To detect a problem with the motors, it 
is necessary to compare actual speed with 
expected speed. If the two differ by more 
than a small percentage, an overload con- 
dition exists, so the motors could overheat 
and be destroyed. The following-error 
words constantly monitor the motors and 
detect a stalled motor by comparing the 



58 



current motor position with the expected 
position. If the difference is too great the 
motors are turned off immediately. This 
also means that if you specify a value of 
acceleration that is too high, a following- 
error will be detected, and the motors will 
be shut down. 

Numeric input 

FORTH normally works with I6-bil 
signed integers. Such numbers can range 
in value from -32768 to +32767. In 
addition, a decimal point may be included 
anywhere in a number and FORTH will 
treat it as a signed double-precision integ- 
er with a possible ranee of 
-2,147.483,648 to +2,147,483,647. 
The position of the decimal point is kept 
in a system variable, DPL. If a number 
without a decimal point is entered, the 
system sets DPL to — I . If a number is 
entered with a decimal point, DPL will 
contain the position of the decimal point 
relative to the least significant digit en- 
tered. A number may have a maximum of 
four digits to the right of the decimal 
point. The FORTH system converts the 
input number to a signed integer repre- 
senting the integer part and a signed integ- 
er representing the fractional part. The 
pair of single precision numbers each car- 
ries a sign bit; the numbers can be used 
alone or together. 

Table I illustrates how various numbers 
are stored. Keep in mind the fact that the 
decimal -point position stored in DPL is 
correct only for the last number entered by 
the user from the keyboard. Numbers 
compiled into a definition do not affect the 
value of DPL after compilation. You must 
be in the decimal base (base 10) when 
entering numbers with decimals. 

The word FIXED converts the last 
number input to an integer and a fraction. 
FIXED gets the value from DPL and puts 
it on the stack, then it calls (FIXED). We 
defined the separate word (FIXED) to do 
the actual conversion, because it can be 
made more general — it can convert any 
number, even if it was not entered from the 
keyboard. 

EXTRACT strips the fraction digits 
from the number one by one until all have 
been removed. That leaves the integer part 
of the number on the TOS (Top Of Stack) 
with the digits beneath it. The digits are 
reassembled into a single number with 
BUILD. SCALAR produces a value that 
is used to adjust the fraction to the proper 
range. If the unsealed fraction is 9, we 
need to know whether it is 9000/10,000. 
9/10,000. or another value. 

The word FRACTION takes a fraction, 
an integer, and a multiplier and creates a 
double-precision integer. So the value 
-932.015 converted by FIXED is a frac- 
tion and an integer. Taking these two 
numbers and a multiplier of 1000 would 
give us the double precision number 
-932015 as follows: 



TABLE 1— NUMERIC STORAGE 


Input 


Value 


Size 


DPL 


725 


725 


16 


-1 


-1 


-1 


32 





1.2 


12 


32 


1 


-9.999 


-9999 


32 


3 


38.04 


3804 


32 


2 



932.015 FIXED 1000 FRACTION. 

FRACTION is used by many other words 
to convert values for internal use. 

User-input conversion words 

Several words convert user-input values 
to more basic units the hardware can use 
for the move commands. 

Distances are entered in units of 
INCHES, FEET, MILES and DE- 
GREES. INCHES takes the value spec- 
ified and converts it to internal form. The 
input value and a scale factor are saved for 
later conversion. FEET takes a distance in 
feet and MILES takes a distance in miles. 
The scale factor is set appropriately for 
each word in terms of the number of 
inches each word represents. DEGREES 
calculates how far each motor must move 
to make the specified turn. 

Speed can be entered in miies per hour 
by using the word MPH, inches per sec- 
ond by IPS, feet per second by FPS, and 
feet per minute by FPM. Each of those 
words stores the value and an appropriate 
scale factor for later conversion. 

G converts the input value (in terms of 
the acceleration due to the earth's gravity, 
i.e., 32.2 ft/sec/sec) to a count that is used 
to accelerate or decelerate the motors, if 
necessary, each time speed is updated by 
the interrupt routines. 

Motion 

To move from one point to another, the 
motors must be accelerated and decele- 



rated. By allowing the user to set a value 
for acceleration, deceleration, and max- 
imum speed, the behavior of the robot can 
be controlled precisely. 

Before a move is actually made, the 
software does a series of calculations to 
determine the top speed that can be at- 
tained, and the positions at which acceler- 
ation should end and deceleration should 
begin in order to attain a trapezoidal ve- 
locity curve, as shown in Fig. I. 

Calculated speed may be less than de- 
sired speed, but that is not a problem for 
short moves. Maximum speed will be 
used for moves that are long enough to 
allow the motors to accelerate to their 
maximum velocity. For short moves, ac- 
celeration is more important than max- 
imum speed. 

To perform a move, breakpoints on the 
trapezoidal velocity curve must be found. 
The points where acceleration ends and 
deceleration begins, as well as the end 
point position, must be calculated. 

The robot is a speed-controlled system, 
so the acceleration and deceleration 
breakpoints must be used to calculate 
what speed will be achieved by accelerat- 
ing at the specified value of acceleration 
to the breakpoint position. That new 
speed is saved with the breakpoint posi- 
tion. The same values of speed and dis- 
tance are used to calculate the breakpoint 
where deceleration is to begin. 

Trapezoidal velocity control 

To perform a move, the robot must be 
accelerated from a speed of zero to top 
speed, and then decelerated at the appro- 
priate point to arrive at the desired posi- 
tion. The simplest system would just set 
the speed of the motors, turn the motors 
on until the end point was reached, and 
then turn the motors off. That type of 
approach assumes instantaneous acceler- 
ation and deceleration, but in an actual 



































































































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TIME 

FIG. 1— ACCELERATION AND DECELERATION BREAKPOINTS must be calculated In order to move 
the robot from one point to another. 



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system it's not practical. Therefore, we 
have to take into account the acceleration 
that actually can be achieved by the sys- 
tem. In practical terms, acceleration 
might be a fraction of G, or it could be 
several G's, depending on the size of the 
motors in relation to the size of the load. 

To accelerate and decelerate the robot, 
velocity actually must be changed many 
times per second. In general, the robol 
starts with a velocity of zero and then 
accelerates at a constant rate to the top 
speed. Then it must decelerate at a con- 
stant rate until it stops at the final position. 

The velocity-versus-time profile is also 
shown in Fig. I, but superimposed on the 
velocity trapezoid. Note that the position 
profile is not simply a straight line. In 
terms of calculus, position is the integral 
of speed over time. The basic equations of 
motion are as follows: 

V = Vp + AT 

D = V T + V4AT 2 

where V stands for velocity, A for acceler- 
ation, T for time, and D for distance. V Q 
refers to starting velocity. 

From the previous equations we can 
derive an equation that describes the dis- 
tance required to accelerate from one 
speed to another: 

D = (V2 - V 2 ) / (2A) 

We can use that equation to compute the 
distance required to change speeds. 

For a short move, the distance required 
to accelerate to the desired speed and then 
decelerate to a stop may exceed the dis- 
tance to move. In such a case, decelera- 
tion must begin at some speed less than 
maximum. 

The word DISTANCE takes the origi- 
nal speed and the desired speed (both in 
rpm) and calculates the distance in inches 
that will be required to change speeds. 
The word COUNTS changes the distance 
from inches to position-encoder counts. 
The word EXPECTED converts the user- 
input distance to position-encoder counts. 
The word SPEED converts the user-input 
maximum speed into rpm. 

The word BREAKPOINTS calculates 
the positions on the velocity trapezoid to 
stop accelerating and begin decelerating. 
The acceleration and deceleration seg- 
ments can't be more than half the total 
move distance, so the distance to acceler- 
ate from to the input speed is calculated 
and compared to half the move distance. 
The minimum of these two values is then 
used as the acceleration distance. The 
breakpoint positions are saved in arrays 
for use during the move. 

After the robot starts moving, the 
breakpoint positions are compared 
against the current position every time the 
control loop executes to determine when 
acceleration should stop and deceleration 
should begin. If the move distance is long 
enough, there will be a period during 



which the motors run at maximum speed. 
For a short move, acceleration will stop 
before maximum speed is attained, and 
deceleration will start immediately after 
acceleration stops. 

Command language 

The RCL includes a simple command 
set to allow movement of both the base 
unit and the arm. 

The base-movement commands allow 
forward and backward motion, and left 
and right turns. Maximum speed, acceler- 
ation rates, and move distance may all be 
altered by user input. After each move is 
complete, a new move command can be 
executed. By denning FORTH words we 
can chain several move commands to- 
gether in a motion sequence. We'll dis- 
cuss such a sequence shortly. 

The arm commands move the arm up 
and down, and open and close the jaws. 



Command syntax 

In general, a command consists of a 
device name, a speed value, a distance 
value, and the command: 

[DEVICE] [n SPEED] [n DISTANCE] 
COMMAND 

where bracketed quantities indicate op- 
tional values that will be: the value 
entered with the command; the last value 
if a new value is not included; or a default 
value if this is the first time the particular 
command is issued. The value of n de- 
pends on the command. DEVICE may be 
RERB for the base unit or ARM for the 
arm unit. 

Base commands 

The general syntax for the base-move- 
ment commands is as follows: 

[RERB] [n SPEED] [n DISTANCE] 
COMMAND 

COMMAND may be one of the follow- 
ing: FORWARD, BACKWARD, LEFT, 
or RIGHT. SPEED may be one of the 
following: MPH, IPS, FPSorFPM. DIS- 
TANCE may be one of the following: 
INCHES, FEET, MILES or DEGREES. 
The command G is used to set the ac- 
celeration constant used to change speed; 
the constant is expressed in G's of acceler- 
ation. Any acceleration may be specified, 
up to the maximum acceleration the sys- 
tem can achieve. The acceleration may be 
specified in a separate command. 

Arm Commands 

The basic syntax for the arm- movement 
commands is as follows: 

[ARM] [n DISTANCE] COMMAND 

COMMAND may be one of the follow- 
ing: UP, DOWN, OPEN, or CLOSE. 
DfSTANCE may be INCHES or FEET. 
DISTANCE is the amount specified in the 
COMMAND direction relative to the cur- 
rent position. 



The example program shown in Listing 
I illustrates how you can combine several 
RCL commands to cause the robot to tra- 
verse a square. The sequence first sets the 
acceleration constant to 0,1 G. Then the 
RERB device (i. e., the base) is selected 
to move at 25 .5 inches per second. Then it 
moves 3.5 feet forward and makes a left 
turn. The latter actions are repeated three 
times so that the robot ends up where it 
started. 

Here's a short routine that moves the 
arm down and then back up: 

ARM 3.1 INCHES DOWN 2 INCHES UP 

By defining FORTH words we can 
create macros to perform various func- 
tions. For example, Listing 2 shows a 
macro that will cause the robot to traverse 
a box of any size. 

Example program 

Now let's show how the robot could be 
used to collect and deliver office mail. 
Figure 2 shows the office layout that we 
will use in the example program. Trays for 
incoming and outgoing mail are attached 
to the robot. 

The overall sequence of operations 
goes like this: The robot starts from a 
"nest," and travels around the corridors, 
waiting at several locations for people to 
retrieve and deposit mail and then returns 
to the mail room. 

We defined several low-level FORTH 
words for the program. To allow the robot 
to wait for different time periods, we de- 
fined several words to execute time de- 
lays. See Listing 3. The first is MS, which 
waits for the specified number of millise- 
conds. The next is SECONDS, which 



LISTING 1 


.1G ( 3.22 ft/sec/sec) 


RERB 25.5 IPS 


3.5 FEET FORWARD 90 DEGREES LEFT 


3.5 FEET FORWARD 90 DEGREES LEFT 


3.5 FEET FORWARD 90 DEGREES LEFT 


3.5 FEET FORWARD 90 DEGREES LEFT 



uses MS to delay the specified number of 
seconds. The last is MINUTES, which 
uses SECONDS to delay the specified 
number of minutes. 

Next we define several words for con- 
venience and to improve the readability of 
the source code. The robot will announce 
its arrival at each place it stops. That is 
done by sounding a beep. The word AT- 
TENTION generates the beep. 

WARNING, sounds several short 
beeps. It is used to avoid running over 
anyone when the robot is ready to move. 

Since all the turns in our model office 
arc at right angles, it's convenient to de- 
fine left and right 90° turn words, TURN- 
LEFT and TURN-RIGHT When the 
robot starts its trip it must back out of the 
continued on page 80 



60 



A NEW KIND OF MAGAZINE FOR ELECTRONICS PROFESSIONALS 



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PUBLICATION 



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Contents 

AUGUST 1987 



Vol. 4 No. 8 




67 MICRO-FLOPPY RETROFIT 

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69 DESIGNING PC BOARDS ON YOUR 
COMPUTER 

Smartwork, AutoBoard, and other PC- 
based CAD packages. 



Computer 
Dices? 



Larry Stickler, 

EHF, CET: publisher & editor in chief 



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63 EDITORS WORKBENCH 

Hardware: The new IBM's 

(Models 30 and 50) 
Software-. Memory Minder disk drive 
analyzer 
RS-232 network program 



Art Kleiman, 

editorial director 
Brian C. Fenton, 
managing editor 
Jeff Holtzman 
technical editor 
Byron G. Wels, 
associate editor 

Carl Laron, 

associate editor 

Robert A. Young, 

assistant editor 

Teri Scaduto 

editorial assistant 

Ruby M. Yee, 

production director 

Karen Tucker, 

production advertising 

Robert A. W. Lowndes, 

production associate 

Marcella Amoroso 

production assistant 

Andre Duzant, 

technical illustrator 

Jacqueline P. Cheeseboro 

circulation director 

Arline R. Fishman, 

advertising director 



ComputerDigest 

Gernsback Publications, Inc. 

500-B Bi-County Blvd. 

Farmingdale, NY 11735 

ADVERTISING SALES 516-293-3000 

Larry Steckler 
Publisher 

NATIONAL SALES 

Joe Shere 

1507 Bonnie Doone Terrace 

Corona Del Mar, CA 92625 

714-760-8967 

Cover Photo by Jeff Holtzman and 
Andre Duzant 



EDITOR'S 
WORK- 

Bench 




68000 UPDATE 



We've just finalized arrangements with 
Peter Stark, a long-time member of the 
microcomputing community to do a series 
of articles that will, be of great interest to 
anyone interested in Motorola's 68000 fam- 
ily of microprocessors, and to anyone who 
wants to learn about computer-system de- 
sign from the ground up. The series will 
center around a gradually upgradable CPU 
board that has been custom-designed spe- 
cially for readers of ComputcrOigcst. A 
minimal system can be brought up for 
about $200; it requires only a serial ASCII 
terminal or any personal computer and a 
communications program to operate. 

The computer can be populated on- 
board to include one megabyte of RAM, 
floppy-disk controller, battery- backed 
clock, Winchester interface, serial and par- 
allel ports, and more. It will also include 3-5 
IBM-compatible expansion slots, in which 
you can pi ug a monochrome ISM PC display 
adapter In addition, the motherboard will 
accept an IBM PC keyboard. (Of course, it 
will also accept low-cost clone compo- 
nents as well.) Using a PC display adapter 
and keyboard will allow you to easily create 
a low-cost stand-alone development sys- 
tem 

The bare-bones system will include an 
EPROM-based monitor program called 
HUMBUG, which derived its tongue-in- 
cheek name from a series of different BUG 
programs, all of which were based on 
Motorola's original MIKBUG program, which 
was used in early 6800 (hundred, not thou- 
sand!) machines. HUMBUG has a number of 
commands for examining and displaying 
memory etc. In addition, we hope to in- 
clude a small version of BASIC in EPROM. 

The expanded computer will run the 
SK*DOS operating system, and possibly 
others. The author of SK*DOS also happens 
to be the author of the series of articles, so 



you'll get a unique first-hand opportunity to 
learn about operating-system design. 
SK*DOS includes a 68000 assembler, a line 
editor, a 6809 emulator, floppy- and hard- 
disk support, extensive file-manipulation 
facilities, etc. 

As for the MC68000 computer we pre- 
sented in the March and May issues this 
year, we should have the promised informa- 
tion packet ready by mid to late summer In 
addition, Peter Stark has adapted SK*DOS 
to run on the MC68000, although no formal 
system of distribution has been set up. We 
should point out, however, that the new 
(and as yet un-christened) machine will 
have better local support and distribution. 

All in all, we're very excited about this 
project; we hope to begin the series in 
October or November For more informa- 
tion, check our BBS (516-293-2283) occa- 
sionally, and watch these pages for 
announcements of progress. 




IBM'S NEW MODEL 30 AND MODEL 50 
PC'S 



In case you missed it, IBM introduced four 
new personal computers last spring. They 
go by the name of Personal System/2, al- 
though only the three high-end machines 
(the Models 50, 60, and 80) have the new 
high-speed (and incompatible) Micro 
Channel bus, and only they will be able to 



take advantage of the new operating system 
OS/2, which we'll be lucky to see by early 
next year However, the low-end machine 
(the Model 30) is not without merit; we 
examined one, and a Model 50. 

All aboard 

The new low-end machine can be view- 
ed as a souped- up PC or XT, depending on 
whether you get it with two floppy-disk 
drives or a hard disk and a single floppy It 
has a bus that is compatible with the old 
bus, and it's a fast (8 MHz) 8086-based 
machine that contains everything on the 
system board that you normally must add 
via expansion cards: 640K of RAM, serial 
and parallel ports, keyboard and mouse 
connectors, battery- backed clock, and vid- 
eo adapter See Fig. 1. Other than the com- 
pact, lightweight system unit, the only thing 
you need to get a Model 30 running is DOS 
3.30 and a monitor 

The video hardware is downward-com- 
patible with the CGA (contrary to our re- 
port last month), and has f^vo new modes 
of its own, including a stunning 256-color 
mode that allows you to create images like 
that shown on this month's cover (page 61). 
The other new mode provides 640 x 480 
resolution in two colors, which should be 
great for CAD applications. The MCGA 
(Multi-Color Graphics Array) is not com- 
patible with Hercules or EGA standards, 
but it may be upgraded (via a plug-in card) 
to the VGA (Video Graphics Array) video 
adapter, which we discuss below, that is 
standard with the other PS/2 machines. The 
VGA is EGA-compatible. 

The Model 30 comes with a disk-based 
set-up/tutorial program that allows you to 
set time and date, park the hard-disk heads 
for moving the system, etc. The tutorial is 
extremely well-done, both in terms of the 
information presented and in the way it is c 
presented. The graphics in the tutorial are -h 
simply stunning,- they drew numerous oons S 
and aahs from our co-workers. The manual ^ 



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S087 MATH 
COPROCESSOR 

8237A-5 DMA 
CONTROLLER 



SYSTEM 
GATE ARRAY 




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8086 
CPU 



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I/O SLOT 1 


I/O SLOT 2 


I/O SLOT 3 



MONITOR 



BEEPER 



VIDEO [ VIDEO 
MEMORY [ SUPPORT 



I/O 
GATE 

ARRAY 



PORTS 



• V.V.V.V.V.W • 



SERIAL 



CLOCK 



SYSTEM 

riMER 



DISK 




BATTERY 



FLOPPY 




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HARD 



PARALLEL 



FIG.1 



el; in the high-res mode, each bit represents 
one pixel. 

Model 30 memory mapping 

According to the Model 30 Technical Ref- 
erence manual, the BIOS can detect the 
presence of an alternate video adapter. 
When it does, it will disable the on-board 
MCGA and use the alternate adapter. 
However, the manual does not specify 
what type of adapter may be used in that 
way So we don't know at present whether 
Hercules, EGA, and other adapters will 
function in the Model 30. But you can add 
the IBM PS/2 Display Adapter, which brings 
VGA-style graphics to the Model 30, as well 
as to the PC and XT models. 

The Model 30s 640K RAM has been im- 
plemented as follows. The first 128K con- 
sists of four 64K by four-bit and two 64K by 
two-bit DRAM's, all of which are soldered 
to the motherboard. The next 512K consists 
of two 256K by nine-bit plug-in SIP RAM 
modules. Those modules are mounted on a 
slant; they're visible at the right side of the 
system unit in Fig. 2. 

A special register (accessible at I/O port 
6Bh) allows each 64K segment of memory 
from 40000h to 9O000h to be disabled in 
case of conflict with memory on an expan- 
sion card or hardware error In addition, a 
special bit in that register apparently allows 
one of the upper banks to be re-mapped to 
the lower 128K segment of memory in case 
there is a hardware problem there. The BIOS 
POST (Power-On Self Test) handles those 
duties automatically 



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is a slim booklet that will neither intimidate 
the novice nor bore the expert, 

In our tests, we found no hardware or 
software incompatibilities. Our test unit ran 
an Ethernet adapter card and a 68000 co- 
processor card without a hitch. Tested soft- 
ware includes: AutoCad 2.6, WordStar 4.0, 
Dr Halo II (version 2.15, specially for the PS/2 
line), SideKick 1.56b, Direc-Link, Brooklyn 
Bridge, Best Friend, PC ED, and numerous 
small utilities. 

The MCGA 

The Model 30s video adapter provides 
better text quality than the old CGA, be- 
cause each character is now displayed in an 
8x16 box, rather than the CGA's 8x8 
box. However, the screen still flickers when 
in the text mode. As many as four character 



fonts may be stored in the OAOOOOh seg- 
ment of RAM (formerly used by the EGA); 
one or two active fonts may be loaded and 
stored in a separate 8K static-RAM character 
generator DOS 3.30 uses the new font ca- 
pability to provide greater support for for- 
eign languages; the new capability should 
also ease implementing any scientific and 
engineering word-processing programs. 
The OBSOOOh area of memory is still used as 
a video buffer, with characters and their 
attributes occupying alternate bytes of 
memory 

In graphics modes, OBSOOOh is still used 
for storage in the old CGA-compatible 
modes,- in the new 256-color and 640 x 
480 modes (11 and 13, respectively), the 
video buffer begins at OAOOOh. In the 256- 
coior mode, each byte represents one pix- 



Model 30 hardware notes 

The Model 30 has three horizontally 
mounted expansion slots; they're visible at 
the rear left in Fig. 2. The edge connectors 
for those slots are mounted to a board that 
in turn plugs into an edge connector on the 
motherboard. The expansion-slot board 
also carries the clock/calendar's backup 
battery,- that battery is soldered to the 
board, and at present IBM only plans to 
replace that board as a unit when the bat- 
tery wears out. 

The BIOS now supports four serial ports; 
previous machines officially supported 




64 



+ NOT AVAILABLE 
* +NQ HARD DISK 





FLOPPY BEAD \ ■¥■ \ 
FLOPPY WRITE \ 



HARD READ 
HARD WRITE " 



IBM PS 2 MODEL 30 



FLOATING POINT MATH 
INTEGER MATH 



IBM PS/2 MODEL 50 
FIG. 4 




FIG. 5 



only two. The parallel port is now bi-direc- 
tional, so you can connect the parallel ports 
of two machines together and exchange 
data between them. In fact, IBM is selling a 
program/cable combination called the 
DataMigrationFacility(DMF)thatall ows you 



to do exactlly that. The DMF could be es- 
pecially useful in transferrins data from an 

old-style machine. 

The keyboard and mouse ports are elec- 
trically interchangeable-either keyboard or 
mouse may be plugged into either port- 



the BIOS separates keystroke scan codes 
from Mouse codes. 

All the I/O connectors are soldered to 
the motherboard. No external disk-control- 
ler cards (for hard or floppy disks) are nec- 
essary The_disk drive handles 720K 3Vs" 
disks, as used in the IBM PC Convertible and 
many other portables. The power supply is 
rated at only 70 watts, but that should be 
sufficient for most users. In addition, sur- 
face-mount technology is used extensively 
as shown in Fig. 3. 

The Model 50 

The Model 50 can be viewed as a hybrid 
of an XT and an AT, with the Micro Channel 
bus (three slots) and OS/2 compatibility 
thrown in forsood measure. The model 50 
has a 10-MHz one-wait-state 80286 micro- 
processor, which is faster than the AT's mi- 
croprocessor,- but it has a relatively slow, 
relatively small (20 megabytes) hard-disk 
drive like the XT 

The floppy-disk drive can read the 720K 
format used by portables and the Model 
30; it also can read and write a new 1.44- 
megabyte format. You cannot format a 720K 
diskette for 1.44-mega byte use; special dis- 
kettes are required. The Model 50 also in- 
cludes a megabyte of RAM, and a full 
complement of I/O ports. 

We tested the Model 50 and found it to 
be quite fast. See Fig. 4 for a speed-com- 
parison chart. The Model 50 ran all the soft- 
ware we tested it with: WordStar 4.0, Dr 
Halo II version 2.15, numerous system util- 
ities, including a special communications 
program that manipulates the serial port 
directly — and everything we tested 
worked without a hitch. Of course, we 
couldn't test any expansion boards, be- 
cause none are available yet. 

The VGA 

The Model 50 s Video Graphics Array 
hardware is compatible with all previous 
IBM display adapters (monochrome, CGA, 
EGA, and MCGA), and it adds several new 
display modes of its own, including: 

• 640 x 480 sraphics in 16 colors (the 
MCGA provides only two colors at that res- 
olution); 

• 720 x 400 alphanumeric in 16 colors or 
monochrome; 

• 360 x 400 alphanumeric in 16 colors. 
Of course, the VGA can also run in the 

256-color mode of the MCGA. By way of 
comparison, the EGA provides 640 x 350 
in 16 colors in graphics mode. Apparently 
the VGA is not compatible with the Her- 
cules monochrome standard. 

It's worth pointing out that all supported 
modes will run on any PS/2 monitor That 
differs from most present multi-mode vid- 
eo adapters, which can run in various 
modes, but only on appropriate monitors 
(TTL monochrome, color, or enhanced 
color). There's much more to say about the 
VGA, but, unfortunately no space to do so 
at this time. 



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Model 50 hardware notes 

As with the Model 30, surface-mount !C's 
are used extensively; plug-in cards extend 
appropriate signals from the motherboard 
to the floppy- and hard-disk drives. One 
very interestins feature of the Model 50 is 
the modular way in which all the sub-sec- 
tions snap together For example, as shown 
in Fig. 5, the floppy-disk drive snaps into 
place, and the edge connector provides 
mechanical as well as electrical contact (A 
plastic guide system beneath the unit locks 
it into place.) The hard-disk drive mounts in 
a similar manner, as do the bus -extender 
cards, and even the fan. 

The Model 50 includes three Micro Chan- 
nel bus slots (shown in Fig. 6); its sibling, the 
Model 60 (which we didn't evaluate), 
provides eight slots and a faster hard disk. 

Monitor mania 

There are several monitors available for all 
the new models; two are color displays 
(8512, 8513) and one is monochrome 
(8503). They all have the same resolution 
(720 x 400 in text mode, 640 x 480 in 
graphics mode); they differ mainly in price 
and size. Our cover shot was made with the 
8512 monitor, a 14-inch model. 

The new monitors are analog types, 
which means that they are incompatible 
with the previous standards, although NEC 
has announced that their MultiSync monitor 
is compatible with the addition of a cable 
adapter. The new monitors are plug -com- 
patible with each other; the BIOS senses 
whether a color or a monochrome display 
is connected and routes signals according- 
ly If a monochrome monitor is attached and 
a color mode is active, the RGB signals are 
summed and output to the monitor via the 
DAC (Digital-to-Analog Converter) that 
controls green. 

It's unclear at present whether two 
monitors can function simultaneously; 
some CAD programs and debuggers use 
one screen for menus and control functions, 
and the other for program output. 

New BIOS and DOS 

The following discussion refers to the 
Model 30s BIOS and DOS 3.30. A new 
BIOS interrupt lOh function call (12h) 
provides a means of switching various vid- 
eo adapters on and off. Again, it's unclear 
whether external Hercules, EGA, or other 
adapters are supported. 

Another new BIOS interrupt function (In- 



terrupt 15h, function 4Fh) allows you to in- 
tercept keyboard scan codes as they are 
generated (via interrupt 9). The new func- 
tion allows you to change the scan code, or 
cause it to be ignored altogether That func- 
tion will aid remapping keys for foreign- 
language and technical word processing, 
but without resorting to illegal interrupt 
stealing as some word-processing and key- 
board-enhancing programs do. Another 
keyboard function (Interrupt 16h, function 
5) allows you to stuff the keyboard buffer 
with key codes as if those keys had been 
typed. 

A number of other BIOS functions are not 
clearly documented, but seem to point in 
the direction of adding multi -tasking ca- 
pabilities to the machine, 

DOS 3,30 is not a major upgrade, but it is 
not insignificant either It contains greatly 
expanded support for foreign-language 
character display, extended network sup- 
port, and extended batch -file support, in- 
cluding a CALL command that allows one 
batch file to call another. (CALLing was pos- 
sible but awkward in previous versions of 
DOS.) The new DOS also supports all disk 
formats, ranging from the single-sided sin- 
gle density (160K) SV< format of the original 
PC to the 1.44 MB format of the models 50, 
60, and 80. DOS 3.30 runs on all past and 
present models of the FC 

Conclusions 

All in all, the PS/2 machines represent real 
technological improvement in the PC family 
They are not a radical departure from past 
systems, nor are they misplaced machines 
like the PC Jr and the PC Portable. Rather, 
they represent an incremental step in the 
evolution of the PC family They're not the 
cheapest machines, but they set standards 
that others will follow. We applaud IBM's 
leadership efforts, and hope that it will con- 
tinue in the course it has set itself. 

Credits 

Media Cybernetics (8484 Georgia Ave., 
Suite 200, Silver Spring, MD 20910, 
800-446-HALO) graciously sent us a beta- 
test copy of version 2.15 of Dr Halo, which 
supports the new video hardware; we 
used it to create our cover image. And 
thanks to AutoDesk, Inc. (2320 Marinship 
Way Sausalito, CA 94965), for sending a test 
copy of AutoCAD version 2.6. Thanks to 
Andre Duzant for cover art, and to Herb 
Friedman for cover photography|Q>4 



MEMORY MINDER, DISK-DRIVE 
ANALYZER FROM J&M SYSTEMS 



Mechanical devices are always the first 
to go. In particular, disk drives are a 
primary source of trouble. To help you spot 
a potential problem before it develops into 
a catastrophe, you can take your drives to a 
repair shop for testing. Or you can buy a 
disk-drivs, analysis program for about the 
cost of two trips to the repair shop and run 
the diagnostics yourself. 

One such program is called Memory 
Minder It's sold by J & M Systems, Ltd. 
(15100A Centra! SE, Albuquerque, NM 
87123, 505-292-4182), and it lists for $114. 
The package consists of three parts: a man- 
ual, a disk containing the control program, 
and a special test disk. The program disk 
uses the test disk to check drive speed, 
head and clamping alignment, and several 
other factors. 

How to run it 

First you boot your machine directly from 
the Memory Minder program disk. It then 
displays a menu that lets you select param- 
eters and run tests. After booting, the pro- 
gram disk is no longer needed; at that point, 
you insert the Digital Diagnostic Disk(DDD), 
manufactured by Dysan, into the desired 
drive. Disks are available for testing several 
types of drives. 

From the main menu you first run a clamp 
test (shown in Fig. 2), which tests the ac- 
curacy with which a diskette is clamped. If 
your drive can't pass the clamping test, 
chances are it can't pass any other tests 
either (It's also possible that the DDD has 
gone bad, in which case it must be re- 
placed for the healthy sum of $40.) 

Then you run a quick test, whose screen 
appears as shown in Fig. 7). Ifyourdrive fails 
any aspect of the quick test, you can run 
more-detailed tests. For example, spindle 
speed may be measured directly in RPM, 
and, if speed varies from the standard (300 
RPM for a 5y4-inch drive) by more than 
± 2%, the program tells you so. 

Another test checks the drive's head 
alignment. J&M provides generic instruc- 
tions for aligning a head, and wisely refers 
you to the manufacturer's alignment instruc- 
tions. Other tests check other aspects of the 
drive's operation, and a special set of rou- 
continued on page 72 



66 



K RCTROFIT 




Retrofit your PC or XT with a 3 1 /2-inch disk drive. 



HERB FRIEDMAN 

if you use an IBM PC or clone, you maybe underwhelmed by all 
the fuss being made about S'/s-inch disks. However; many porta- 
ble computers, and all of IBM's new line of PC's, use 3^-inch disks. 
(See "Editor's Workbench" for reviews of two of the new PC's.) The 
small diskettes have many advantages over the SVi-inch disk you're 
used to using, include 

• Increased capacity (two to four times that of a standard 360K 
floppy disk) 

• Greater reliability because each disk is completely enclosed by 
a hard plastic shell 

• Smaller, shirt-pocket size 

SVWnch disks are by no means obsolete, but chances are that the 
industry will move steadily toward use of 3'/?-inch disks, just as 8- 
inch disks were gradually supplanted by 5 'A -inch disks. So in this 
article we'll showyou how to retrofit your computer to use 3 1 /s-inch 
disks. Then you'll be ready to handle the upcoming new wave of 
software and data. We'll discuss installation of IBM's model 
2683190 disk-drive retrofit kit for PC and XT model computers. 
Similar kits are available from clone manufacturers, but installation 
may differ, so your drive's instructions carefully 

What it is 

The retrofit kit consists of a cabinet- mounted 3 s k- inch disk drive 
with attached signal and power cables, a y-adapter that lets you tap 




S*w 




FIG. 1— THE CABLE FROM THE ZVvmtih drive has its own power 
connection take-off that matches the miniature power socket on 
the supplied Y-adapter. The ring through which the adapter's 
power wire loops is a toroid choke that help suppress RFl. 



power from your computer's internal disk-drive power connector 
(shown in Fig. 1), and a kit of three pre-punched metal brackets 



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67 






(shown in Fg. 2) that accept the Y-adapter's connector: 

installation is simple. First you mount the appropriate bracket on 
the rear apron of your computer Then you install the V-adapter in 
series with one of the existing internal disk-drive power con- 
nectors. Next, you push the small power connector through the 
hole in the bracket. That connector locks in position by means of 
mounting ears molded on the connector Finally you connect the 
cable from the3'/9-inch disk drive to the controller card in your main 
computer. 

With some PC's you won't need to install the power cable in 
series with the floppy power connector The reason is that the 
power supplies in some PC's have four power connectors. So, if 
you haven't used used all four, just connect the V-adapter to one of 
the unused connectors. 

Use the bracket that causes the least inconvenience. For exam- 
ple, if you use the relatively large standard rear-slot bracket shown 
in Fig. 2, you must give up an entire slot. Some PC's have only five 
slots, so it may prove impossible for you to use the large bracket. In 
that case you could use the smallest bracket, which will mount in 
the small hole abwe the cassette port (yes, the original PC included 
a cassette interface). The medium-size bracket can be used in the 
extra slot above the keyboard port on an XT. 

Clone panel layouts may vary so you" might have to use the full- 
size bracket and give up a slot. Or you might just cut a hole of your 
own in which to mount the small bracket. 

Standard controller 

To use the adapter, you must have an an IBM-type floppy-disk 
controller, the. kind with a 37-pin D-connector on the mounting 
bracket (as shown in Fig. 3), in addition to the resular floppy-disk 




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FIG. 4— THIS IS A TYPICAL CLONE INSTALLATION. The disk- 
controller socket and the 3'/2-inch drive's power socket are on 
adjacent brackets. 




FIG. 5— CONNECTORS IN PLACE AND BEADY FOR USE. The 37- 
pin D-connector is a real heavyweight, so be certain that you 
tighten its mounting screws to ensure reliable operation. 



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FIG. 2— THE RETROFIT KIT is supplied with three different 
brackets for the power sockets. Use the one that's most conve- 
nient for you, but remember that the standard bracket (the large 
one) may force you to give up use of one expansion slot. 




FIG. 3— IBM-TYPE DISK CONTROLLER cards have a 37-pin sock- 
et on the rear for external disk drives (C: and D:). The retrofit cable 
must connect to that socket. 



connector. The IBM control I er accommodates four floppy- disk driv- 
es: two internal and two external drives. Because the retrofit kit 
connects to the computer via the external 37 -pin connector, you 
cannot use a mu It i -function disk controller (the kind that combines 
a disk controller, serial and parallel ports, a joy-stick interface, and a 
clock), because it has no connector for external floppy-disk drives. 
The controller itself needn't be an actual IBM device; having the 
external connector is the important point. 

Figure 4 shows an XT clone ready to connect the 3'/s-inch disk 
drive. The external disk-drive connector is adjacent to the miniature 
power connector installed in the slot furthest left. 

To install the 3V?-inch drive, simply plug the appropriate con- 
nectors from the drive in the appropriate jacks, as shown in Fig. 5. 



Device driver 

Before you can use your new drive you must tell the computer 
that it's there by adding a device driver to your computer's CON- 
FIG.SYS file, the configuration file that's automatically read when the 
computer boots. For example, adding the line: 

DEVICE = DRIVER.SYS /D:2 

to your CONFIG.SYS file will allowyou to access a 3Vs inchdisk drive 
as the next available drive (D: on an XT). IBM's device driver comes 
only with DOS versions 3.20 and 3.30, (Some clone manufacturer's 
drives are available with drivers that work under DOS 2.11. — Editor) 
The device driver informs your computer that the 3'/&-inch drive 
exists, establishes its physical parameters, including number of 
tracks, sectors per track, number of heads, etc., and sets the drive's 
logical designation (D:, E:, F:, etc.) 



68 



DESIGNING PC BOARDS 

ON YOUR 
COMPUTCR 




ROBERT GROSSBLATT 



Last ti m e, i n the J une i ssue, we exam i ned CAD ( Com p u te r Aid ed 
Design) in a general way seeing what kinds of things you can do 
(or should be able to do) with any worthwhile CAD package. This 
month we'll look at several specific packages, focusing on those 
that are of special interest to the electronics enthusiast. 

There are a number of packages on the market, and both price 
and performance vary considerably However, none of the pack- 
ages we reviewed are inexpensive. As we've seen, a layout pro- 
gram must contain several different but integrated parts, so a 
complete package represents a substantial investment in develop- 
ment time. In addition, the potential market is small, certainly much 
smaller than the markets for word-processing and database pro- 
grams. So development costs and market size translate into rela- 
tively high prices. 

smARTWORK 

The Wintek Corporation markets a package called smARTWORK, 
which probably is the most popular of the "inexpensive" routing 
packages. It has a graphics editor, router, and is capable of produc- 
ing high-quality output. The program is an "interactive" router — 
what we call a point-to-point router. After you place the compo- 
nents, you can draw traces yourself or tell the router which points 



you want connected together. smARTWORK wi 1 1 do its best to lay in 
the traces. 

The Wintek program only does the PC-board layout; there's no 
way to draw the schematic, generate a netlist, and have the router 
read the file. So using smARTWORK is in some ways similar to doing 
a layout by hand on graph paper 

smARTWORK is simple to use. After loading the program and 
creating a file, you begin your layout by placing the doughnuts and 
pads. The coordinates of the cursor are always shown on the 
bottom of the screen; that makes it simple to put a component in a 
precise location in the workspace. There area variety of pad shapes 
available, as well as commands to create various patterns for ICs 
(SIP and DIP layouts, for example) headers, and soon, automatically 

The finished layout is really the parts-placement diagram for the 
board you 're designing, so it's a good idea to work out a rough idea 
of where things are to be placed before you start smARTWORK 
Doing so will make it easier to avoid going beyond the edge of the 
board as well as to take into account any of the special placement 
considerations we've already mentioned. It's easy to make adjust- 
ments to the board when you begin routing the traces because 
smARTWORKs graphics editor has a set of commands to let you 
move, stretch, delete, and fill. 



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When you start routing traces, smARTWORK will let you do either 
a single- or a double-sided board, with an optional silk-screen 
layer. However, keep in mind the fact that the program can only 
handle two routing layers. If you want to do multilayer boards, you'll 
have to use another package. Each layer can contain two trace 
widths, thin and fat, and although you can choose between three 
preset thin widths, you can only use one on each layer The fat 
width, 50 mils, is the only one available, but you can produce a 
fatter trace by laying two or more traces near each other 

Routing can be done either by hand or by using the routing 
algorithm built into the progtam. However you do it, chances are 
that you'll want to rearrange traces as the layout develops — and 
that's where you'll appreciate the power of the graphics editor. It's 
easy to change anything on the board — it's really as simple as 
moving text around in a word processor. 

When tne design is complete, you can get hardcopy from a dot- 
matrix printer in either actual board size or double size. There are 
commands to control the intensity rotation, and size of the printed 
output As shown in Fig. 1, a much higher-quality printout can be 
obtained by using a plotter; smARTWORK supports several Which- 
ever device you use, smARTWORK will generate camera-ready art 
for photochemical board fabrication, Wintek can supply you with 
information about hardware compatibility 

Wintek markets another program called HiWIRE, a graphic sche- 
matic-drawing editor, and they're currently working on software 
that will let the two programs share common data files. Contact 
them directly at the address shown in the sidebar for more detailed 
information. 

Another company (Creative Electronics) is marketing a program 




FIG. 2— SMARTWORK also produces quality copy on a dot-matrix printer. 



(smARTCAD) that converts smARTWORK files into AutoCAD format. 
(We discuss AutoCAD below) When you do convert a file, each 
side of your PC board will be on a separate layer, and you can use 
any AutoCAD editing command to do tilings you just can't do with 
smARTWORK. For example, you can: 

• Add text in any size and font. 

• Place pads for odd-sized components. 

• increase board size beyond 10 x 16 inches. 

• Use a different grid spacing. 

• Prepare a solder mask. 



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FIG. 1 — SMARTWORK produces high-quality camera-ready work when- 
used with a good plotter. 



Project :PCB 

A new low-priced entry is called Project :PCB; it's made by 
DASOFT Designs, Inc., and it has many features that are missing from 
smARTWORK, including a means for schematic capture and a true 
auto-router; The circuit diagram can be entered with a graphics 
editor; the program can extract the net list directly from the drawing. 
You can also enter and edit connections in text form directly from 
the keyboard. The software comes with a limited component 
library but you can use a parts editor to build new parts that can 
then be called up automatically when you're entering a schematic. 

In fact, ProjectiPCB actively encourages you to create symbols 
and share them with others,- the company has set up a bulletin 
board (415-486-0862) where users can share custom parts and 
libraries, and where the company will post information on updates, 
bug fixes, new versions, etc. 

To use Project: PCB, first you create the schematic. When it's 
finished, you use the layout editor in a graphics mode to define the 
overall shape of the board and to place the components. Then 
you're ready to route the board. It can be done automatical iy with 
Project:PCB by selecting the Route option on the menu, or you can 
enter traces manually before turning the router loose on the layout. 
One of the nicest features of the program is the ability to tell the 
router to do only a single net and then stop. That means that you can 
pre-route power and ground lines, for example, before going on to 
the rest of the board. 

The router goes over the board twice But you can set it up to do 
only one side of the board and then stop. That gives you the 
opportunity to try to improve the layout by hand, and then have the 
router go through that side again. Doing the layout that way can be 
valuable, because feedthroughs are the inescapable con- 
sequences of double-sided boards, and plated-through holes are 
difficult to do at home and expensive to do commercially 

Project:PCB can deliver hardcopy to a variety of plotters, but 
printer output is limited to text dumps of the various data files that 
are generated by the program. If you have one of the plotters 
supported by the program you'll get beautiful camera-ready art- 
work that's perfect for board production. 

The program has more stringent hardware requirements than 
smARTWORK. Much of the equipment (mouse and plotter, for 
example) that is optional with smARTWORK is required to run 



70 



ProjectiPCB. But ProjectiPCB has a much more extensive graphics 
package, as well as an auto-router 

Autoboard 

At the other end of the price/performance spectrum is a program 
called Autoboard. It is designed for serious production. It has every 
feature we've already discussed, and many many more. In fact, 
comparing it to the packages we've been discussing is like compar- 
ing a Ford to a Ferrari — they're in different leagues altogether Of 
course, the added capabilities don't come for nothing. 

In order to concentrate all their energy on the routing package, 
the Great Softwestern Company decided to look elsewhere for the 
graphics editor That was a wise decision. 

Autoboard, in addition to its auto-router, is a collection of over- 
lays, script files, menus, macros, and drawings to turn AutoCAD into 
an electronics graphics package. It goes without saying that Auto- 
CAD is one of the most powerful and most supported graphics 
editors on the market. So one of the great strengths of Autoboard is 
that it makes full use of AutoCAD. The schematic and board layout 
are entered in AutoCAD; Autoboard s custom menu system makes 
it simple to do so. 

While building the schematic or the board, you can use any of 
AutoCAD's awesome range of commands to edit the drawing 
you're working on. The parts library from Autoboard is extensive, 
and you can create new parts by building their definitions in a word 
processor — a straightforward procedure that's described in the 
manual. 

Autoboard is designed for commercial board fabrication, so it 
has some impressive capabilities: 

t. It can route boards up to 16 layers thick. 

2. It can handle more than 1000 components on a board. 

3. More than 40 buses can be defined. 

4. You can have as many IC arrays as you want. 

5. More than 1000 pins can be tied together 




FIG. 3— AUTOBOARD routed this board automatically using a schematic 
created with AutoCAD. 



TABLE 1— PROGRAMS DISCUSSED 

smARTWORKS The Wintek Corporation 
1801 South Street 
Lafayette, indiana 47904-2993 

$895.00 Copy Protected 

Project: PCB DASOFT Designs Systems, Inc 
P.O. Box 8088 
Berkeley, California 94707-8088 

$950.00 Hardware Locked 

The Autoboard The Great Softwestern 
System Company, Inc. 

207 W. Hickory St. Suite 309 
Denton, Texas 76201 

$2500.00 Requires AutoCAD 

AutoCAD Autodesk, Inc. 

2320 Marinship Way 
Sausalito, California 94965 

$2850.00 (Version 2.5 or above) 

smARTCAD Creative Electronics 
925 Fairwin Ave. 
Nashville, Tennessee 37216 

$395 



6. Board dimensions can be up to two feet square 

The fourth item in that list deserves a little explanation. Some IC's 
(memory devices, for example) are put on a board as a block, and 
the traces that connect them are laid out in a standard fashion. 
Autoboard has built-in algorithms to generate those traces, and 
there are routines in the graphics editor to place the IC's on the 
board with proper spacing. 

The best way to indicate how Autoboard works is to describe 
the process of creating a board. Remember that you must own a 
copy of AutoCAD (and know how to use it!) in order to use 
Autoboard. 

The first Step, as with ProjectiPCB, is to tell Autoboard about the 
schematic you're using. There are a series of batch files that do all 
the setup work for you (open data files, call up AutoCAD, and load 
a series of custom menus and scripts). Parts are chosen from menus 
along the right side of the screen,- AutoCAD prompts you for 
orientation and location. As you move the cursor around the screen, 
the part you're working with drags along until you place it. Next 
you're asked for the part's number and value. Last, AutoCAD draws 
the part on the screen along with the other information. 

When the parts are all placed and identified, you connect them 
together using either AutoCAD's Line command or the Line macro in 
the Autoboard menus. There's a difference. Autoboard s Line com- 
mand will automatically place the line in the correct layer for the 
software that reads the drawing file and generates the list of con- 
nections. You can switch between layers using the normal AutoCAD 
commands, but it's simpler to use the macros. 

When the drawing is sized, titled, and completed, a special 
command converts the schematic information to a netlist for use by 
the rest of the program; it also makes sure you don't have any 
unconnected components or lines. If it finds any it lets you know by 
listing them on the screen as text — but that's not all. 

One of the layers that Autoboard defines when it sets up Auto- 
CAD is called the Warning layer. If there are any uncommitted pins, 
unterminated lines, etc., Autoboard will return you to AutoCAD, 
and the points in question will have small red circles around them. 



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EDITOR'S WORKBENCH 



continued from page 66 



tines aid in performing a traditional align- 
ment by allowing you to position the head 
to any track. 

Each test is activated from its own screen 
from which you can select the drive to test, 
the head (0 or 1) to test, and the location on 
the DDD to test. You can print any screen by 
choosing the appropriate menu item. In ad- 
dition, a setup screen allows you to estab- 
lish specific operating characteristics, 
including disk type, serial-port parameters, 
main or alternate test tracks, etc, (The alter- 
nate tracks on the DDD are provided so that 




FIG. 7 

you can continue to use the disk after the 
first set wears out.) 

Recommendations 

Memory Minder is rather expensive for 



hobbyist use. However, if you split the cost 
amons several persons, each of whom 
might use the program two or three times a 
year, Memory Minder is worthwhile. The 
manager of a small office with a number of 
PC's could easily justify the cost of the pro- 
gram, and if he uses it conscientiously it 
could prevent valuable data from being 
lost, and thereby make an employee very 
happy 

What to do with the information Memory 
Minder provides is another story If you have 
no experience alisning disk drives, it's 
probably best to leave well enough alone, 
unless you're willing to experiment and 
possibly pay the consequences. But as a 
diagnostic aid, Memory Minder is a well- 
thought-out, easy-to-use product.|<D| 



72 



MICRO FLOPPY DISK DRIVES 



continued from page 68 



You can access the disk tike this: The 3'/9-inch drive is automat- 
ically assigned the next available drive letter (after all floppies and 
hard disks, if any). For example, if your hard disk is drive G, the 37s- 
inch drive becomes drive D:. If you have two hard drives, G and D:, 
the 372-inch drive becomes drive E:. If you have no hard disk, but 
you do have a RAM disk set up as drive G, the 37s-inch drive again 
becomes drive D:. 

Logical and physical 

You may wonder whether you can copy a file from one 37a-inch 
diskette to another without going through an intermediary device 
such as a hard disk, a RAM disk, or even a 5Y*-inch floppy disk. You 
can (using DOS 3.20 or DOS 3.30). What you do is enter the device 
driver program into the CONFIG.SYS file twice. For example: 



DEVICE 
DEVICE 



= DRIVER.SYS,'D:2 
= DRIVER.SYS '0:2 



The computer is then fooled into thinking that there are two 
physicdt 3Ya-inch drives with different logical designations (D: and 
E;, for example). DOS will prompt you to switch disks when that is 
appropriate. 

That's not as complicated as it may sound. It's really the same 
capability we've always had with the ISM, but extended to handle 
more drives and more types of drives. If you've ever copied a file 



from A: to 8: on a machine with only a single floppy-disk drive, you 
know how it works. 

For example, assume that you have a single floppy drive and a 
hard disk. The floppy functions as drives A: and B: and the hard disk 
functions as drive G. You can install two device drivers that tell the 
computer that the 37e-inch drive will function as both D: and E:. 
Now there's no problem copying files between separate 334-inch 
disks via a single drive. The computer will prompt you when to 
swap disks. 

You might prefer to do it this way: Use the motherboard's DIP 
switch to program four floppies, even if you have only two. The 
hard disk automatically becomes drive E:. Configure the device 
driver so the 372-inch drive is G. That will leave D; free for use as a 
RAM disk. Then the entire disk lineup will be A: and B: as 574-inch 
floppies, Gas a 37s-inch floppy D: as a RAM disk, E: as the hard disk, 
and F: as the second logical designation for the 37a- inch floppy 

Setting up the device driver can become somewhat compli- 
cated, but bear in mind that, when it's over, to interchange data 
between any combination of disk drives, you can use the normal 
DOS COPY command. 

One final point: There are a number of different 3Vs-inch disk 
formats. For example, the Tandy Model 100 disk drive has one 
format, the Macintosh computers have another, and IBM now has 
two of its own, both high-density (1 .44 megabyte) and low-density 
(720K). The high-density format is used only in the new Models 50, 
60, and 80; the low-density format is used in the new Model 30, 
IBM's laptop, as well as laptops from a number of manufacturers 
(including Zenith, Toshiba, etc ) The upgrade described here can 
read only the low-density IBM forma t.|(D4 



COMPUTER DESIGNED PC BOARDS 



continued from page 77 



To correct a mistake, you can connect an uncommitted point using 
the Dot command, which draws a small blue circle there and 
informs Autoboard that you want a connection. If the pin was left 
open by design you can just isnore the warning. 

The next step is to define the board and place the parts. Once 
again, Autoboard has a set of files that customize AutoCAD with 
menus and macros. After the board outline is defined, you can 
begin laying the parts out in much the same fashion you did when 
the schematic was drawn. Pic kins a P art f rom a menu allows you to 
drag it around the screen and place it exactly where you want it. 

It's a tremendous help to use AutoCAD's Zoom command to zero 
in on a location if you're placing a small part. The drawing of the 
part you drag around the screen will be enlarged by the same 
amount, so you'll be able to judge relative placement and size. 
Once you've picked the insertion point, you'll be asked for the 
name of the part and its value. They must be consistent with those 
you used in the schematic entry phase, because Autoboard's router 
. uses those names to identify the parts and also the connections in 
the netlists. 

When you complete the layout, you can hand-route some traces 
if your circuit has requirements you're afraid won't be properly 
addressed by the router Next you'll want to turn the auto- router 
loose; that's done simply by giving it the name of the board you 
want routed, 

Autoboard is an open system in that all the menus and script files 
(and many other parts of the program) can be customized to fit 
your requirements. The same is true, to a lesser extent, of the router 
There are a series of "switches" you can set in the router that control 
things like the number of allowable layers, minimum and maximum 
pad and trace widths, spacing, time limits, and soon. That is easily 
done by editing a configuration file with a word processor The 
router automatically looks for that file when it starts to run. If it can't 
find it, it uses its default values. 

There's something magical about watching the router in opera- 



tion because it constantly reports its progress on the screen. Our 
example board was one that had already been done by hand (we 
showed it last time), and it was amazing, to say the least, to watch 
Autoboard do in 15 minutes what had taken two days to do by 
hand. The only consolation was that all connections were made in 
the hand- routed board, but Autoboard missed five (out of a total of 
115). That's not a bad percentage, and it's a safe bet that tweaking 
the configuration file could result in a success rate of 100%. 

The last thing the router does is call up AutoCAD, draw the board 
on the screen, and display all the traces it has finished. It creates a 
separate "rats-nest" layer for the missed routes and draws them on 
that layer in a different color It also creates a text file with a BAD 
extension that lists all the connections it missed. By the time reach 
this point, you're in AutoCAD looking at the routed board with each 
board layer in a separate AutoCAD layer (including separate ones 
for the pads and the silkscreen). Now is when you'll appreciate the 
fact that Autoboard works inside AutoCAD. You can use any Auto- 
CAD command to do anything you want to any layer — you have 
complete control of the drawing. 

When you're happy with the layout, you can use any of Auto- 
CAD's normal output commands. So you can create a text file that 
describes the board (for conversion to FutureNet, Gerber, etc.), or 
you can print it, plot it, etc. AutoCAD knows how to talk to virtually 
every printer and plotter ever made, so you can be confident it wi 1 1 
talk to yours. And AutoCAD files are one of the few standards for 
graphic data. As for input devices, some sort of digitizing tablet is 
tremendously helpful in drawing both schematics and layouts. 
And, as with printers and plotters, AutoCAD knows how to talk to 
just about all of them. The keyboard, of course, can be used alone 
or in conjunction with a digitizing tablet. 

Conclusions 

Each of the packages we've been talking about is a well-thought- 
out piece of software, and each is updated occasionally All the n 
graphics produced for this article were done on an IBM PC XT with a g? 
Sigma Designs Color400 Video Board, an SR-12 monitor from i- 
Princeton Graphics, and a Summamouse from Summagraphics, 3 
And a very special bit of thanks must go to Dennis Jump for ® 
standing by the phone.^CD^ < 



73 



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SATELLITE TV 



continued from page 29 



end up selling the TV viewers a 
better picture in order to attain an 
international standard. 

Why an international fuss about 
the technical nitty-gritty that goes 
into a TV picture? Because there is 
a crying need for a universal televi- 
sion standard. High-tech com- 
munication systems, such as 
satellites, can now beam a TV pic- 
ture from any part of the world to 
any TV set, so there must be a con- 
venient way for everyone to view 
programming from any spot on the 
globe. Since there are three wide- 
ly-used television standards now 
in use — NTSC, the North Amer- 
ican or US standard; PAL, the basic 
all-Europe standard; and SECAM, 
the joint French-Russian stan- 
dard — the exchange of television 
programming such as the Olym- 
pics, and news feeds, and even 
family programming, has been a 
burden because the equipment 
that converts one TV standard to 
another is expensive and prone to 
failure. 

While it is possible to manufac- 
ture a receiver capable of receiving 
the three types of TV signals, they 
are, and are likely to remain, pro- 
hibitively expensive. Multi-stan- 
dard receivers, such as those that 
are available in small quantities in 
Europe and the Middle-East, are 
not cost-effective because a major 
portion of the circuitry must be 
duplicated, even triplicated, to ac- 
commodate the different trans- 
mission standards. 

Whose HDTV? 

Television formats, as we know 
them today, originated in the 30's 
and 40's. (NTSC color was appen- 
dixed to an existing black-and- 
white standard in the 50's.) Even if 
we could conveniently and inex- 
pensively interchange the signal 
formats, all of the systems, NTSC, 
PAL, and SECAM, realize approx- 
imately half of the picture defini- 
tion that's possible using 1980's 
technology. 

Although present technology 
makes a 1,000- to 1,200-line video 
transmission system do-able at 
consumer prices — European, Jap- 



anese, and North American firms 
all have such systems operating — 
like the NTSC/PAL/SECAM de- 
velopments, no two of the pres- 
ently developed systems share the 
same standards, so we're back 
with the same old problem. 

Many engineers believe that 
there is general worldwide ac- 
knowledgment that we must avoid 
entering the era of HDTV with 
three different "national stan- 
dards," and that since the present- 
day transmission standards are 



ready to be replaced, a serious 
effort should be made to adopt 
new standards it will resolve the 
50-year old problems related to 
multiple, non-compatible sys- 
tems. Unfortunately, it will require 
uncommon resolve to push the 
strong nationalistic instincts into 
the background in favor of a sin- 
gle, worldwide-technology stan- 
dard. If it happens, it will be the 
first time that the world has agreed 
on an important broadcasting 
standard. R-E 



Radio Electronics 



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-« 5 INCHES *- 

USE THIS BOARD to assemble the digital tachometer's display board. The article appeared in the June 1987 
issue. 



+ 



+ 




+ 



-4-1/16 INCHES- 




THE MAIN BOARD for the digital timer is shown here. You can find the story beginning on 
page 45. 



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76 



AMP DESIGN 



continued from page 56 



BASE BIAS 
VOLTAGE < 

DIVIDER 




FIG. 1— A COMMON-EMITTER AMPLIFIER was 
the ideal solution to our design problem. 




FIG. 2— SIMPLE CALCULATIONS yielded the 
component values shown here. 



through R I is a combination of the volt- 
age-divider current plus the base current. 
The base current is equal to the collec- 
tor current divided by beta. It is found 
from: 

l B - 1.28/100 = 0.0128 mA 

So the total current through R I is 0.054 
mA + 0.0128 mA = 0.067 raA, and R] 



= i 0.8/0. 067 m A = 160,000 ohms. 

Resistor Rl is the most critical resistor 
in the circuit. To ensure maximum voltage 
swing, it should bring the quiescent col- 
lector voltage to one half the supply volt- 
= 10.8/0.067 mA = 160,000 ohms. 

Resistor Rl is the most critical resistor 
in the circuit. To ensure maximum voltage 
swing, it should bring the quiescent col- 
lector voltage to one half the supply volt- 
age. After building the circuit, the value 
of Rl may have to be varied slightly to 
achieve that voltage swing. 

We now have a circuit we can test. 

Interfacing 

Connecting the circuit to the outside 
world will require capacitor coupling. 
That serves to isolate the AC signal front 
any DC bias voltages. Figure 3 shows our 
complete circuit with input and output 
coupling capacitors. The values of those 
capacitors were calculated using C = 
1/(3.2 X / x R), where C equals the 
capacitor value in farads, /equals the fre- 
quency at which response will be down I 
dB, and R equals the impedance on the 
load side of the capacitor. 

To calculate the value of CI , the ampli- 
fier's input impedance (I5K) is used for R. 
To calculate the value of C2, the input 
impedance of the next stage (50K) is used 
for R. 

The value of CI can now be calculated 
foradropofldBat20Hz:Cl = 1/(3.2 X 
20 X 15000) = .00000104 farad =1.0 
p.F. The value of C2 = 1/(3.2 x 20 x 
50000) = .00000031 farad = 0.33 p.F. 

To increase the gain of the stage, you 
could bypass R b with a capacitor, as 
shown in Fig. 4. Nothing comes for free, 
however. The price you pay for increased 
gain is lower input impedance, which will 
vary widely with beta. If that variation is 
not a problem, a significant gain increase 
can be realized by adding the bypass ca- 
pacitor. Our original circuit has a gain of 
10; if the emitter is bypassed the gain 
becomes R c /0.03/I li = 4700/(0.03 / 
0.00129) = 4700/23 « 200. 

The value of the bypass capacitor in 
farads is calculated from the formula C = 
1/(6.2 X / X R). Again / is the low- 
frequency limit in Hz, and R is the dy- 
namic emitter resistance (0.03/I R ), In our 
example, if we stick to a 20-Hz lower limit 
we have C = l/[6.2 x 20 X (0.03/ 
0.00129)1 = .000344 farads = 344 p.F. A 
350- p.F unit can be used. 

Computerized calculations 

It only seems natural to put the comput- 
er to work to lessen the drudgery of doing 
repetitive mathematical calculations. The 
BASIC program shown in Listing 1 is 
written to do just that. In addition, it 
serves as a sort of scratch pad for your 
designs, and allows you to do several 
"what-if" calculations easily. The pro- 
gram was written for a Commodore 64, 




FIG. 3— CAPACITOR COUPLING is required to 
interface the amplifier to the outside world. 



+ 12V 



Rl jj 



160K 



CI . 

I.DnF' 



INPUT 



I 



Re 

470011 



^CT 



R2 

22K 



EMITTER 
"BVPAjS 

C3 
v 350u-F 



T 



C2 
-33nF 



OUTPUT 



470!! 



FIG. 4— INCREASE GAIN by bypassing the emit- 
ter resistor as shown here. 

but it can be modified to run on any other 
system. 

A few thoughts on components before 
we finish: Using 5% resistors allows 
closer adherence to the calculated values. 
Because of their temperature stability and 
low leakage specifications, silicon rather 
than germanium transistors are preferable 
for this type of circuit. 

Finally, you've no doubt noticed that 
we have yet to specify a specific transistor. 
That's because for this type of application 
it really doesn't matter! Almost any 
small-signal device will do fine. B-E 



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COMMUNICATIONS CORNER 



continued from page 31 



dB greater than the signal received 
by a single antenna. A special de- 
tector samples the signal-to-noise 
ratio of the received signal on a 
half-cycle basis. If out-of-phase 
multipath reception at one anten- 
na causes the signal-to-noise ratio 
to fall below a minimum value, the 
detector automatically inserts the 
delay line by opening the elec- 
tronic switch, thereby flipping the 
phase of the signal from antenna b 
by 180°, which in turn causes the 
delayed signal to add once again 
to that of antenna a. 

To avoid constant switching 
back and forth, which might dis- 
tract the listener, the detector is 
designed so that it maintains the 
phasing as long as the received sig- 
nal is strong enough to be usable. 
Only if new or changing multipath 
signals degrade the "out of phase" 
signal to an unacceptable value 
will the detector cause the delay 
line to switch out. 

Some of you familiar with selec- 
tive fading on the high-frequency 
shortwave bands will wonder what 
happens to the receiver's volume 
level when the signal varies within 
the allowed range (before it falls 
low enough to activite the delay- 
line switching). The answer is that 
nothing happens; there is no 
change in volume level. On the 
shortwave frequencies, all signals 
are AM or single sideband (which, 
of course, is only a variation of 
AM), so tbe volume level from the 
speaker will vary if the signal level 
breaks away from control of the 
AGC (/Automatic Cain Control) or 
the AVC (Automatic Volume 
Control); that's a condition abso- 
lutely bound to occur during se- 
lective fading. 

But wireless sound equipment 
uses FM modulation, whose re- 
ceived volume level depends on 
deviation, not signal strength. 
Only if the signal falls to an almost- 
useless level is there any effect on 
an FM signal's volume level, and 
the receiver squelch circuits will 
mute the sound long before the 
listener hears a change in volume 
level caused by the received signal 
strength. R-E 



Electronics KnTOD 





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79 



RE ROBOT 



continued from page 60 



LISTING 2 


: BOX ( feet -— ) 


RERB 


25.5 IPS 


2DUP (FEET) FORWARD 


90 DEGREES RIGHT 


2DUP (FEET) FORWARD 


90 DEGREES RIGHT 


2DUP (FEET) FORWARD 


90 DEGREES RIGHT 


2DUP (FEET) FORWARD 


90 DEGREES RIGHT; 



LISTING 3 



: MS ( milliseconds — ) 
?DO 33 DO LOOP LOOP ; 

: SECONDS ( seconds — ) 
0?D0 1000 MS LOOP; 

: MINUTES ( minutes — ) 

?DO 60 SECONDS LOOP 




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LISTING 4 

: ATTENTION ( — ■ ) 

BEEP BEEP 1 SECONDS ; 

: WARNING ( — ) 

5 DO BEEP 1 SECONDS LOOP ; 

: TURN-AROUND ( — ) 

RERB 10 IPS 180 DEGREES 
LEFT; 

: TURN-LEFT ( — - ) 

90 DEGREES LEFT ; 

: TURN-RIGHT ( — ) 

90 DEGREES RIGHT ; 

r AHEAD ( feel — ) 

FEET FORWARD ; 

: COLLECT ( minutes — ) 

ATTENTION MINUTES WARNING : 



recharging area and turn around to go 
forward. The word TURN-AROUND 

makes a 1 80° turn. The word AHEAD is 
shorthand tor u forward move. COLLECT 
combines the ATTENTION. WAITING, 
and WARNING functions, because we al- 
ways use them together. The definitions of 
those words are shown in Listing 4. 

A frip consists of backing out of the 
techarger and exiting the mail room, mak- 
ing a clockwise trip around the office, 
slopping at several points (including a 
long stop at the president's office), and 
finally returning to the mail room. The 



FIG, 2— MODEL OFFICE FOR THE EXPERIMENTAL TRIP program that is shown in Listing 5. 





LISTING 5 






; TRIP ( -— ) 








WARNING 


RERB 


20 IPS 


3 FEET 


BACKWARD 


TURN-AROUND 


2.5 AHEAD 




TURN-RIGHT 


12 AHEAD 


TURN-LEFT 




5 AHEAD 


TURN-LEFT 


36 IPS 




10 AHEAD 


TURN-RIGHT 


2 COLLECT 




7 AHEAD 


2 COLLECT 


8 AHEAD 




TURN-RIGHT 


25 AHEAD 


TURN-RIGHT 




3 AHEAD 


2 COLLECT 


11.5 AHEAD 




4 COLLECT 


11.5 AHEAD 


TURN-RIGHT 




ATTENTION 


3 COLLECT 


( President) 




14 AHEAD 


TURN-LEFT 


4.5 AHEAD 




TURN-RIGHT 


12 AHEAD 


TURN-LEFT 




10 IPS 


5.5 AHEAD 







word TRIP executes the entire program; it 
is shown in Listing 5. 

TRIP only causes the robot to make one 
excursion around the office, but we want 



LISTING 6 

MAILBOT ( — ) 

8.5 AM WAIT-UNTIL TRIP 
9.5 AM WAIT-UNTIL TRIP 
10.5 AM WAIT-UNTIL TRIP 
11.5 AM WAIT-UNTIL TRIP 
1.5 PM WAIT-UNTIL TRIP 
2.5 PM WAIT-UNTIL TRIP 
3.5 PM WAIT-UNTIL TRIP 
4.5 PM WAIT-UNTIL TRIP 



the robot to make several trips during the 
day. without having to tell it to do so each 
time. We can schedule the trips when de- 
sired using the words AM, PM, and 
WAIT-UNTIL. WAIT-UNTIL simply 
waits in a delay loop until the current time 
is identical to the desired time. AM and 
PM set the desired time. Time is specified 
in hours, so minutes must be expressed as 
fractional hours. For example, 8,5 AM is 
8:30 am. The entire MAILBOT program 
is shown in Listing 6. 

You can extend RCL to deal with addi- 
tional hardware and to provide greater 
software flexibility. FORTH gives you the 
freedom to experiment and add to the ca- 
pabilities of the system. R-E 



80 






STEREO RECEIVER 



continued from page 44 



The IC's AGC function was noi used in 
the design. Instead, pin 16 was terminated 
by R40andC33. 

A 10.7-MHz tuned circuit is formed by 
L7. C3iS. and C37. Resistor R4I acts as a 
swamping resistor to obtain the wide 
bandwidth of the quadrature circuit, C37, 
C38, and L7. Drive voltage from pin 8, IF 
out. to pin 9. quadrature detector input, is 
delivered via L6. The value of that induc- 
tor is somewhat critical for proper 
squelch-circuit operation. It should be be- 
tween 18-22 p.H. We had an 18-u.H unit 
on hand so it was used. 

A load for the AFC circuit is provided 
by R43, and R42 biases the audio circuit 
in the iC, Capacitor C38 is used to tune 
the quadrature circuit to 10.7 MHz. It is 
adjusted for best received audio and zero 
DC voltage across R43. 

Recovered total modulation is present 
at pin 6, It contains the FM baseband and 
the SCA signal. The baseband audio is 
taken off through R44 and C39. 

The baseband-audio amplifier is built 
around Q6, a 2N3565. It is set up for a 
nominal gain of about 5 (the ratio of R44 
to R46 is the approximate gain of this 
stage). Resistors R45 and R46 bias Q6 to 
about 6 volts at I mi Hi ampere. R47 is a 
load resistor. About 2 volts of baseband 
audio is present at the collector of Q6. 

Audio from Q6 is fed to two separate 
circuits. One circuit is an SCA demod- 
ulator; the other is an FM stereo decoder. 

SCA demodulation 

Audio from Q6 is fed to an SCA take- 
off R-C high-pass filter made up of C40. 
R48, R49, C41, C42. and R6S. That filter 
substantially attenuates audio compo- 
nents below 50 kHz. 

The SCA demodulator, 1C2, is an 
LM565 phase-locked loop. It contains a 
VCO (Voltage Controlled Oscillator) and 
phase detector comparator. If a signal of 
sufficient amplitude (about 100 millivolts) 
is fed into pin 2 or 3 of that device, and its 
frequency is sufficiently close (say within 
±30%) to the VCO frequency, the VCO 
will lock to the input frequency and track 
it; that is. the voltage that controls the 
VCO will follow any changes in the fre- 
quency of the input signal. The control 
voltage for the VCO is present at pin 7 and 
is a linear function of the input-signal 
frequency. Therefore, the LM565 can 
function as an FM detector with no exter- 
nal inductive components required. (At 
the SCA-subcarrier frequencies of 67 or 
92 kHz. inductors can become rather 
large and somewhat costly. It is therefore 
to our advantage to eliminate those coils, 
and their alignment.) 

The LM565 is biased by external re- 



sistors RSI, R52, R53. and R54. The 
VCO frequency is determined by C43 and 
the resistance of R72 and R55. Theseitim: 
of R72 is adjusted so that the VCO I're- 
quency. which can be measured at pin 4. 
is near 67 kHz. 

Adjustment of R72 is not critical, and 
simply adjusting it for clearest SCA re- 
ception is adequate. (If 92 kHz operation 
is desired, R55 should be changed to 
about 6.8K.) Capacitor C44 is used as a 
loop filler for the phase- locked loop. Au- 
dio appears at pin 7 of the LM565. A de- 
emphasis network made up of R56, C45„ 
RS7. and C46 will suppress any 67-kHz 
components and attenuate high-frequency 
noise. 

An audio-amplifier stage, Q7, brings 
up the detected audio level to about 500 
mV. From the amplifier, the signal is sent 
to the selector switch. S2, for routing. 



FM decoding 

Audio from Q6 is also sent, via block- 
ing capacitor C49. to 1C3. an LML310N 
FM-stereo multiplex decoder. The 
LMI310N contains a VCO, a phase- lock- 
ed loop for regenerating the 38-kHz stereo 
su be airier, a lock detector used as a ster- 
eo-indicator circuit, and a decoder circuit 
for deriving the left and right audio chan- 
nels. The internal VCO operates at 76 
kHz and the 19-kHz and 38-kHz signals 
are derived from an internal frequency 
divider. No indicators are required and 
alignment consists simply of adjusting 
R73 for a 19-kHz signal at pin 10. 

Getting back to the circuit. C53, R62, 
and C54 form a compensating network for 
IC3"s internal phase-locked loop. Capaci- 
tor C50 is the loop filter for the phase- 
locked loop. The network made up of 
C55, R63. and R73 control the center 
frequency of the internal VCO, which 
should be 76 kHz. The 19-kHz pilot signal 
(derived from an internal divider) is avail- 
able at pin 10 for test purposes. Audio 
output appears at pins 4 (left) and 5 
(right). Resistors R64 and R65 serve as 
loads for the internal audio amplifiers. 
FM-audio de-emphasis is provided by 
C56 and C57. The right and left audio 
from pins 4 and 5 is fed to S2. 

The audio amplifiers in this circuit, 1C4 
and IC5, are LM386N\s. They each 
provide about a 0.5-watt output, adequate 
for driving an eight-ohm speaker. Do not 
use speakers that present less than an 
eight-ohm load. 

The entire receiver draws about 125 
milliamps at 12-volts (the recommended 
supply voltage). The supply should be 
regulated and have good filtering. A suit- 
able power supply is shown in Fig, 3. 

Next time 

That's all the room we have for now. 
Next lime we'll show you how to build, 
align, and use the receiver. The PC pattern 
will he presented at that lime. R-E 



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CIRCLE 111 ON FREE INFORMATION CARD 



LEARN TV/VCR 
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Now you can train at home In spare lime for a mon- 
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No need to quii your job or school. Wc show you how 
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almost any make of television or VCR, You learn about 
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find out how you can start making money In this 
great career, ( 

Experts show you what to do, how to 

do it^.guide you every step of the way! 

Everything is explained in easy*to*underst4nd language 
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there is ever anything In your lessons you don't under- 
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can count on getting an authoritative answer. Send for 
free facts and color brochure. Mo cost. Ho obligation. 
No salesman will visit you. MAIL COUPON TODAY i 



_ SCHOOL OF TV VCR REPAIR. DepL DE077 
wuc .nfj Scranton, Pennsylvania 18515 
Please send me free facts on how I can learn TV/VCR 
Repair at home in my spare time, No salesman will visit. 



Name 



. Age 



City/State/Zip 
Phone ( ] 



> 

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c 



GO 
^-4 



81 



MARKET CENTER 



FOR SALE 



CO 

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RESTRICTED technical information: Electronic 
surveillance, schematics, locksmith! ng. covert sci- 
ences, hacking, etc. Huge selection. Free bro- 
chure MENTOR-Z, 135-53 No. Blvd.. Flushing, NY 
11354- 

TV lunable notch filters, free brochure. D.K. VIDEO, 
Sox 63'6025, Margate, FL 33063. (305) 752-9202. 

FREE power supply with Assortment #103 
(February '84 article, has printed circuit, 
TOKO C0i!s(4), 2N3904{2), BFQ85, 7812, 
74123, JVSC1330. 1N914, 1M5231B. TELE- 
ASE-MAST ASSORTMENT #301 (October 
Article) Printed Circuit with all IC's, tran- 
sistors, diodes. Only S25.00'each assort- 
ment. Five/$112.50. Shipping S3. DO. 1 
(800) 821-5226 Ext. 426. (orders), or write 
JEM RHODES INC., P.O. Box 3421. Bristol, 
TH 37625. 

DESCRAMBLER catalog all makes. Special com- 
bo Jerrold 400 and SB3 $165. New cable de- 
scrambler kit $39.00 (assembles in half hour). Send 
$1.00. MJ INDUSTRY, Box 531, Bronx, NY 10461. 

TUBES! 59c, Year guarantee. Free catalog. Tube 
tester $8.95 CORNELL, 4215 University, San Di- 
ego, CA 92105. 

IS it true... Jeeps for S44 through the government? 
Call for facts! 1 (312) 742-1142, ext. 4673. 

OLDTIME radio programs on high quality tapes. 
Comedy! Adventure! Music! Free catalog. CARL F. 
FROELICH, Heritage Farm. New Freedom. PA 

17349. 

LINEAR PARTS— transistors: MRF454 $15, 
MRF455 $12, MRF477 $11, MRF492 S16.75, 
MRF421 $22.50, SRF2072 $13, SRF3662 S25, 
3800 $18.75, 2SC2290 $19.75, 2SC2879 $25. 
Tubes: 6KD6 $10.50, 6LQ6 $9.75, 6LF6 S9.75, 
8950 $16.75. Best prices on Palo mar road noise 
mics, Ranger AR330Q. New 16-page catalog listing 
radio/amplifier tricks — channel modification, PLL- 
sliders, peaking for range, hard-to-find linear 
parts — mail $1.00 to: RFPC, Box 700, San Marcos, 
CA 92069. For same day parts shipment, call (619) 
744-0728. 



TUBES - 2000 TYPES 
DISCOUNT PRICES! 

Early, hard-to-lind, and modern tubes. 
Also transformers, capacitors and 
parts for tube equipment. Send $2.00 

tor 20 page wholesale catalog. 

ANTIQUE ELECTRONIC SUPPLY 

688 W. First Sl.'Tempe, AZ 85281*602/894-9503 




CABLE TV converters. Scientific Atlanta, Jerrold. 
Oak, Zenith, Hamlin. Many others. "New" Video 
Hopper "The copy killer," VHS -wireless remote 
5239.00. Visa, M/C & Amex accepted. Toll free 
1-(800) 826-7623. B&B INC., 10517 Upton Circle, 
Bloomington, MN 55431. 

BUILD your own pro monitors 32 pg. 5 part man- 
ual discloses design criteria utilized by major man- 
ufacturers of pro monitoring systems. Blueprints 
included! $25.00 complete to: BRIX ENTER- 
PRISES INC., 2419 Richmond Road, S.I.N.Y. 
10306. 

SCANNING disk television. Read all about it! "The 
Mechanics Ol Television." (1987) 182 pages $20.00 
postpaid. TESLA ELECTRONICS, 835 Bricken, 
Warson Woods, MO 63122. 

LEADER LFC-945 signal level meter $425.00. (312) 
771-4661. 

TUBES, name brands, new, 80% off list, KtRBY, 
298 West Carmel Drive. Carmel, IN 46032 



ATTENTION looking for surplus test equipment sig- 
nal generator voltmeter oscilloscope. J.B. ELEC- 
TRONICS, 9518 Grand, Franklin Park. IL 60131. 

TEST equipment, reconditioned. For sale. $1.25 for 
catalog. WALTER'S, 2697 Nickel. San Pablo. CA 
94806. (415) 724-0587. 

OLD radio TV schematics. Send $1.00. make, 
model.RADIO MAPS, P.O. Box 791, Union City, CA 
94587. 

ROBOT! kits. Books and Plans! Learn to build your 
own robots. Free catalogs contain hundreds of af- 
fordable robot systems, Explore the world of 
robotics today. Catalog: CEARGS-ROBOTS!, POB 
453, Peterborough, NH 03458. (603) 924-3843. 

LATEST high-performance op-amps, power 
mosfets. First quality. Send stamped envelope for 
list. ANZA INSTRUMENT CO.. Box 60907, Palo 
Alto, CA 94306. 

CABLE television converter, descrambler 
and wireless remote control video equip- 
ment accessories catalog free, CABLE DIS- 
TRIBUTORS UNLIMITED, 116- Main Road, 
Washington, AR 71862. 

LASERS, components and accessories. Free cata- 
log, M.J. NEAL COMPANY, 6672 Mallard Ct„ Ori- 
ent. OH 43146. 



CB RADIO OWNERS! 



We specialize in a wide variety of technical infor- 
mation, parts and services for CB radios. 10M- 
FM conversions, repairs, books, plans, kits, 
high-performance accessories. Our 11th year! 

Catalog $2. 



CBC INTERNATIONAL. P.O. BOX 31500RE. 
PHOENIX. AZ 85046 



SUPERFAST morse code supereasy. Subliminal 
cassette. $10.00 Learn Morse Code in 1 hour; amaz- 
ing new supereasy technique $10. Both $17. 
Moneyback guarantee. Free catalog: SASE. 
BAHR, 2549-E3 Temple, Palmbay, FL 32905. 

TUBES, new, unused. Send self-addressed, stamp- 
ed envelope for list. FALA ELECTRONICS, Box 
1376-2, Milwaukee, Wl 53201. 

TUBES: "Oldest", "latest". Parts and schematics. 
SASE tor list STEINMETZ, 7519 Maplewood Ave,, 

RE Hammond, IN 46324. 

CABLE-TV converters and de scram biers. Low 
prices, quality merchandise, we ship C.O.D. Send 
S2.00 for catalog. CABLETRONICS UNLIMITED, 
P.O. Box 266. South Weymouth, MA 02190. (617) 

843-5191. 

Upgrade CD players, other equipment with Au- 
dio Amateur, world's only audio construction 
quarterly, S18'Year; S3Q.two. Satisfaction guar- 
anteed. MC VISA (603} 924-9464; checks to Box 
S76, Dept. E77, Peterborough, NH 03458-0576. 

ZENITH SSAVI, ready to go $100.00 plus shipping. 
order C.O.D. 1 (305) 752-9202 

FREE sample! Discover Apex screwdriving bits, ac- 
cessories. Sensational fit. remarkable toughness, 
amazing durability. Write today! R, SHOC KEY'S, 
5841 Longford, Dayton, OH 45424. 

DECODE nearly any Gated Pulse signal with our 
new super simple circuit Works on In-band, AM or 
FM pilot tone — use with Hamlin, Jerrold, Sylvania. 
Complete plans and theory only $13.50 plus $1.50 
P&H. ELEPHANT ELECTRONICS INC., Box 
41665-J. Phoenix. AZ 85080. (602) 581-1973. 

VIDEO scrambling techniques, the original "secret 
manual" covers Sinewave. Gatedpulse, and SSAVI 
systems. 56 pages of solid, useful, legible informa- 
tion, only $14.95 ELEPHANT ELECTRONICS 
INC., Box 41865-J, Phoenix, AZ 85080, (602) 
581-1973. 



.P^, WRITE FOR 

.JllkMcGEE'S 

SPEAKER & ELECTRONICS CATALOG 

1001 BARGAINS IN SPEAKERS 
toll free 1-600-346-2433 for ordering only. 

1901 MCGEE STREET KANSAS CITY, MO. 64103 



WHOLESALE car stereos alarms electronics Huge 
selection. Catalog $1.00. NORMAN ELEC- 
TRONICS, Box 3579A Ridgewood, NY 11386. 

BATTERIES rechargable, gel-lead, pure lead Ni- 
cads send for free complete listing of batteries by 
amp/hr and voltage. ENERGY CONTROLS, 20451 
Stephens SI., Clair Shores, Ml 48080.' (313) 
775-3492. 

RESISTORS: 1/4 watt, 5%, all standard values to 
4.7 meg. 20 pieces of one value $1.00 postpaid. 
RAHTEC, Box 36064, Minneapolis, MN 55435. 

PCB volume fabrication from Hong Kong INTEG- 
RITY TECHNOLOGY, 105 Serra Way. #230, 
Mllpitas, CA 95035-0604. 

SURPLUS computers: Multibus, Versabus. S-100, 
VME, AMIGA, Atari ST — boards, power supplies, 
test equipment, terminals, disk drives, complete 
systems. Free catalog. Trading IBM-compatibles for 
unwanted systems: buying unwanted equipment. 
HIGH-TECH SURPLUS, (203) 723-5694. 490 
Wooster Street, Naugatuck, CT 06770, 

TAP complete set volumes 1-84 quality copies Si 00 
ppd PEI, P.O. Box 463, Mt. Laurel, NJ 08054. 

PHOTOFACT folders, under #1400 $3.00. Others 
$5.00, Postpaid LOEB, 414 Chestnut Lane. East 
Meadow, NY 11554. 

EQUIPMENT liquidation: Surplus remote-control 
converters, with touch-type remotes, favorite chan- 
nel programmable, digital PLL synthesized, auto- 
matic fine tuning, switched TV outlet, 30 day 
warranty, $35.00. Quantity package 25+ units 
$15.00(0), field run. as is (includes service manual). 
Oak minicode N1 2 decoders quantity package 25 + 
units $20.00<&, field run. as is. "Beeping . notch 
filter CH3 decoders, 30-day warranty, $15.O0(B, 
quantity 25+ $10.00(u\ field run, as is, shipped 
prepaid. All others add $3.00 unit shipping. Send 
money order to ELECTRONICS PRESS, PO Box 
10009, Colorado Springs, CO 80932. 



LIFETIME 

wnfinaHTY 



Quality Microwave TV Antennas 



High Gam System S99. 95 ( < stuppmg) 
I AMR Higti Gain Syslem S79.95 ( ■ shipping i 
Multi-Channel 1.9 lo 2 1 GHz 
Dealerehlpi. Oty . Pricing, Replacemenl Pirtt 

pmiiips-Tecrt Electronics 

P.O. Box 8533 • ScotlidaJe, AZ 85252 
(602)947-7700 IS3.00 CrrtB ill pHom ordcrttl 

MlsttrCKll • 'Ir.i • COO'S 



TI-99'4A soltware/hardware bargins. Hard to find 
items. Huge selection. Fast service. Free catalog. 
DYNA, Box 690, Hicksville, NY 11801. 

Z-TAC Zenith cable unit only $175.00. Buy 5 at only 
$150,00, or 10 at only $125.00. These units do not 
use block converters, we install our own VHF tuner 
for excellent picture quality. UPS daily. COO accept- 
ed. All orders shipped 2nd day air. 90 day warranty 
on units. Call for information or free catalog or write 
AMCOM, P.O. Box 68391, Virginia Beach, VA 
23455. Phone: (804) 456-5505. 

FREE "National Semi Conductor" pocket cal- 
culator and catalog of car stereo, C.'s, radar detec- 
tors, alarms, accessories. Dirt cheap! Send $4.00 
for postage and handling, ELECTROMANIA, 51 B 
Sunrise Highway, Lynbrook, NY 11563. 



82 




DO YOU 



REALLY 

GET THE BEST BUY 



THEM? 



et's face it: There will always be some outfit 
that can undercut a published price. They 
do it by having no overhead, and no 
responsibility to you, the consumer. 

So, you want that Jerrold 450 

combo? The one that Pacific Gads 

CD.. IRC, is offering for s 1 99 M ? 

Weil, that's a good price, but 

here's what I'll do.. ." What may 

happen is that you may save a 

couple of bucks at the time. But suppose 

there's a problem (and it happens to the best 

of them,) and you call that "Dealer"... This could be what you'll hear: 

"No, Steve isn't here. He moved out, the bum! And he owes me E 437 w on the phone bill! No, I don't 

know about any guarantees on your Gerald, who's that? Listen, if you see that creep..." etc. 

At name CMM CO., you've got an established company who will be here for you, time after time. We may be tough competitors, but we've 

got a soft spot for our clients! Try us, and be treated right — and we'll prove it by giving a one-year warranty on everything we sell. 

Check our prices on scientific Atlanta units) 



ITEM 


1 
UNIT 


10 OR 
MORE 




29.00 


18.00 


Panasonic Wireless Converter tour best buy) 


8800 


6900 




88.00 


69.00 




169.00 


119.00 




29.00 


18.00 




89.00 


58.00 




99.00 


70.00 


'M-36 B Combo unit (Ch 3 output only) 


99.00 


70.00 




109.00 


75.00 




89.00 


58.00 



ITEM 

*Minicode (N-12) with Van Sync 

*Minicode VariSync with Auto On-Off ,.,..-,.,,. .... 

Econocode {minicode substitute) 

Econocode with VariSync 

•MLD-1200-3 ICh3 output) , 

•MLD-1200-2 (Ch.2 output) 

•Zenith SSAVI Cable Beady 

Interference Filters (Ch.3 only) ,.,.,,.,.,... 

•Eagle PD-3 Desorambler (Ch.3 output only) . 

•Scientific Atlanta Add-on Replacement Descrsmbler. 



1 
UNIT 

99.00 
14S.O0 
79.00 
89.00 
99.00 
99.00 
175.00 
24.00 
119.00 
119.00 



10 on 

MORE 

62.00 

105.00 

52.00 

56.00 

58.00 

58.00 

125.00 

14.00 

65.00 
75.00 



CHECK US OUT— WE'LL 
MEET OR BEAT THE OTHER'S 
ADVERTISED WHOLESALE 
OR RETAIL PRICES! 




Pacific Cable Co.. inc. 

7325% Reseda Blvd., Dept. R-08 

Reseda, CA 91335 
(81 8) 71 6-591 4 . (81 8) 71 6-51 40 

• NO COLLECT CALLS! • 

IMPORTANT • When ordering, please have 
the make and model number of the equipment 
used in your area— Thank you! 

*Call for availability 

Prices subject to change without notice 

Jenrdd is a registered trademark o' General Instruments Gctp 



Quantity 


Hem 


Output 
Channel 


Price 
Each 


TOTAL 
PRICE 
































































SUBTOTAL 




California Penal Code #593 -D forbids us from 
shipping any cable descrambling unit to anyone 


Shipping Add 
£3.00 per unit 




residing in the state of California. 
Prices subject to change without notice 


COD & Credit 

Cards— Add 5% 




PLEASE PRINT 


TOTAL 





_ City . 



-Zip. 



D Cashier's Check 
Acct # 



_ Phone Number ( 
D Money Order 



)- 



□ C.O.D. 
. Exp Date — 



DVi$a 



□ Mastercard 



Signature- 



FOR OUR RECORDS 
DECLARATION OF AUTHORIZED USE — I, the undersigned, do hereby declare under penalty of perjury 
lhat all products purchased, now and in the future, will only be used on cable TV systems with proper 
authorization from local officials or cable company officials in accordance with all applicable lederal and 
state laws. 



Dated: 



_ Signed: 



> 

C 

o 

c 

CO 

-I 

CO 
CD 



83 



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CABLE-TV DESCRAMBLERS. You name it! 
You'll get it! Specializing in hard to find 
equipment. Special: Scientific Atlanta com- 
bination with remote $229. C.O.D. any- 
where. (916} 541-8461. NATIONAL CABLE/ 
SO. SHORE INC., 1512 Roswell Road # 229, 
Marietta. Georgia 30067 

PLANS AND KITS 

BUILD this five-digit panel meter and square-wave 
generator including an ohms, capacitance and fre- 
quency meter. Detailed instructions $2.50. BAG- 
NALL ELECTRONICS, 179 May, Fairfield, CT 

06430. 

HI-FI speaker systems, kits and speaker compo- 
nents from the worlds finest manufacturers. For oe- 
tinners and audiophiles. Free literature. A&5 
PEAKERS, Box 7462, Denver, CO 80207. (303) 
399-8609. 

VOICE disguisers! FM bugs! SWL active antenna! 
Receivers! More! Catalog SI. 00 (Refundable): 
XANOI ELECTRONICS, Box 25647, Dept 60P. 
Tempe, AZ 85282. 

PROJECTION TV...Convert your TV to project 7 
foot picture. Results comparable to $2,500 proj- 
ectors... Total cost less than $30.00 plans and 8" 
lens $21 .95... Illustrated information FREE...MAC- 
ROCOMA-GL, Washington Crossing, PA 18977. 
Creditcard orders 24hrs. (215) 736-3979, 

CRYSTAL radio sets, plans, parts, kits, catalog 
$1.00. MIDCO, 660 North Dixie Highway, Hol- 
lywood, FL 33020. 

CATALOG: hobby/broadcasting/1750 meters/ham/ 
CB: transmitters, antennas, scramblers, bugging 
devices, more! PANAXIS, Box 130-F8, Paradise, 

CA 95967. 

FREE catalog 99-cent kits — audio, video, TV. 
computer parts. ALLKIT, 434 W 4th St., West Islip, 
NY 11795. 



Cable TV Converters 

Why Pay A High Monthly Fee? 



Jerrold Products include "New Jerrold 
Tri-Mode," SB-3, Hamlin, Oak VN-12, 
M-35-B, Zenith, Magnavox, Scientific 
Atlanta, and more. (Quantity dis- 
counts) 60 day warranty. For fast ser- 
vice C.O.D. orders accepted. Send 
SASE (60 cents postage) or call for info 
(312) 658-5320. Midwest Electronics, 
Inc./, HIGGINS ELECTRONICS, 5143-R 
W. Diversey, Chicago, IL 60639. MC/ 
Visa orders accepted. No Illinois orders 
accepted. Mon.-Fri.-9 A.M. -6 RM.CST 



WIRELESS remote cable converters $60.00 with 
purchase of selected video Kit. $50.00 boards and 
parts for video and hobby projects from magazines 
and other sources. SA turn on kit $40.00. Video 
dechipher kit $75.00 Call or write for list and details. 
WIZARD, 1(419) 243-7856, 24 East Central. 
Toledo, OH 43606. 

JERROLD gated pulse theory. Twetve information- 
packed pages covering Dl & DIC converter opera- 
tion. Includes introduction to trimode system. $6.95 
plus $1.50 postage and handling. ELEPHANT 
ELECTRONICS INC., Box 41865-J, Phoenix, AZ 
85080. (602) 581-1973. 

DESCRAMBLE the latest video cassette copy- pro- 
tection scheme. Our simple line zapper circuit takes 
the jitter out of your picture. Complete plans and 
theory only $13.95 plus S1 .50 postage and handling. 
PC board and complete kits also available. ELE- 
PHANT ELECTRONICS INC, Box 41865-J, Phoe- 
nix, AZ 85080. (602) 581-1973. 

MINIATURE electronics devices, like James 
Bonds. Catalog $2.00. F&P ENTERPRISES, Box 
51272, Palo Alto, CA 94303-L 



//■T Parts 

// express 



HARDWARE AND ELECTRONICS 




MAGNIFIER LAMP 

■ 4" dioptej magmiying IMvf. 
- U»a up to * ffl wall t»*lb (nel 
included! UL iihim], 11 7VAC 



*26 95 



COPPER CLAD 
PC BOARD 




9" i fl Douole Sided 

W55-30Q 

1B' r x 12" OoublH S*de0 



$-|5D 

S395 



HS-232 DATA SWITCH 




• 3 {Kttilion. rotary Iff* ■ Fully 
shielded. FCC appiOWf 



*27^ 



PIONEER HORN 
TWEETER 




• Frequency response l BOO Id 

15.QOQH2. ■ P{hv«r handling capabil- 
ities H5W RM$, r«omn1 Irequency 



*2/fi-£S0 



*6« 



$5*) 




12" PIONEER WOOFEfl 

* Power 65W RMS * 11 Or, rnipni 
■ 251O25O0 Hi reipanM ■ VA-" 
valet coil 



t 15 s» s-i.395 



TOROIDIAL 
TRANSFORMER 




:^:.:-::n,,i :. ' 



I1MMM >«» *9 M 



FREE CATALOG 



Our new 56 page catalog contains 
thousands of items lhat you need 
every day for do-it-yourseiJ 
projects, produd engineering, 
electronics repair and more. Call us 
today for your f rw copy and start 
saving! 




300 PIECE CAPACITOR 
KIT 




* A y:M" asioi[r?.nrl Cif CFIdrdfl 
viluae end wooing voltign 
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CALL TOLL FREE 
1-800-255-3525 

In Ohio: 1-800-322-3525 
Local: (513) 222-0173 



| • 1 5 ** mofttr UK* QuwiiM 


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. onhf. ■ COP ordin *c#*ptt4. 


2* hour shipping. 


- Shipping cfwge = UPS chart rat* (13,50 mln- 


| 3mum ct\*t$*). Houra B:30 i.m. 


< p.m. EST H-F. 



PARTS EXPflESS INTL INC. 
349 E«il Firal St 
DiylH). OhiD 15402 



CIRCLE 181 ON FREE INFORMATION CARD 



When someone 

in your family 

gets cancer, 

everyone 

in your family 

needs help. 



Nobodj- knoQQ better than 
wc (to how much help anrj 
understanding is needed. Thai's 
why our service and rehabilitation 
programs emphuirc ihc whole 
taJhily, not |usi the cancer patient. 

Among our regular services 
ivc provide in formation and 
guidance to patients and Families, 
transport paricnu to and from 
treatmeoi. supply home can? items 
and assist patterns in their return 
to everyday life. 

tjfc Is what concerns us. 

So you can see wc are even 
moje ihan the research organi- 
zation we are so well known (o be 

No one faces cancer alone. 



f AIWEBKAN COMCSR SOCIETY 



SUPER Octopus circuit tester; plans and user's 
guide; $5.00 to VIEWPOINT, 8405 Glencrest, Sun 
Valley, CA 91352. 

ELIMINATE light and dark from copying new video 
tapes. Schematic S5.95 circuit board $5.00. BLED- 
SOE, TO Box 3892, Central Point, OR 97502. 

DETECTIVES, experimenters. Exciting new plans. 
Hard to find micro and restricted devices. Large 
catalog $5.00 refundable on 1st order. WILSON, 
P.O. Box 5264, Augusta, GA 30906. 

ELECTRONICS surveillance book on eavesdrop- 
ping investigation surveillance includes civil liberties 
outlined by congress (Office of Technology Assess- 
ment). Also covers infrasonic sound (sound below 
hearing) send $17.00 to: COUNTERMEASURES, 
P.O. Box 1021, Rowlett, TX 75088. 

RADIO, free power, modern day crystal set. Send for 
info MERIDIAN SYSTEMS, Box 116, Eliot, ME 
03903. 

ULTRASONIC ranging system measures dis- 
tances from 6" to 35'. I/O is TTL compatible, can be 
connected directly to most computers. Experi- 
menter's kit includes one SN28827 ranging module, 
one Polaroid 50KHz electrostatic transducer, and 
user's manual with data sheets. Great for alarms, 
computer mapping, robotics, etc. $59.95 + $2.00 
postage. S2.50 for COD. I.O. MICRODEVICES, 
P.O. Box 2386. Canoga Park, CA 91306, (813) 
348-8312. 



PAY TV AND SATELLITE DESCHAMBLING 
NOW 120 PAGES 



Schemaiics. theory, bypasses. 13 cable. 7 satellite systems including After 
Dark Vitfre SH.S5. fi Ed Update Only S8.95 fnperuneiHj With V.d- 
EOCifj^lfi^ LalCSl Ctlu \S dcr iirj, — s. :"; «.C lii: : i-; :j d,-:!;i y,'J j)f> '';■::!■ "Y 
two-way. security systems, design S12.95. MDS'MMDS HandbeiQlt . for 
micioMtfe hackers SS.SS Bmlfl SalclHi: Sy-;:---n ■:■. i ■:■;:■;_ lUftC J v !H.;i 
Anyj>$26 Summer alslog SI . 



Sho|iki Electronics Corp. 1327A Niagara St.. 
Niagara Falls. NY 14303. COD s 716-284-2163 



STRANGE stuff. Plans, kits, new items. Build satel- 
lite dish $69.00. Oescramblers, bugs, adult toys. 
Informational photo package 53.00 refundable. Dl- 
RtJO CORPORATION, Box 212, Lowell. NC 28098. 

PAC-TEC enclosure specified in Feb. '87 R-E article 
on Tri-Mode. Pre-d rilled.. $24. 95 plus 52.50 S&H. 
VISA/MASTERCARD accepted. Call (617) 
339-1026 or send to THE HOBBY HELPER, P.O. 
Box 308, Bridgewater, MA, 02324. 

ULTRASONIC pest repeller; Exceptional design! 
Complete quality kit S25.0O, assembled $30.00. 
UFO DETECTING BOOK: Electronic projects, the- 
ories, schematics. $6.00 (NY I 7.5%). UFONICS. 
Box 1847-R, W. Babylon, NY 11704. 

MELODY IC, Piezo element and application sheet 
only $3.00 BELL CERAMIC INDUSTRIES, INC., 
31 Passmore Avenue, Unit 28, Toronto, Ontario, 
Canada M1V4T9. 

DESCRAMBLING, New secret manual. Build your 
own descramblers for Cable and Subscription TV. 
Instructions, schematics for SSAVI, gated sync, 
sinewave. (HBO. Cinemax, Showtime, etc.) $8.95 
+• $1 .00 postage. Catalog $1 .00. CABLETRONICS, 
Box 30502 R, Bethesda, MD 20814. 

SATELLITE descrambting manual, Video Cypher 

II. Schematics, thorough explanation of digital audio 
encoding, EPROM code, DES. (HBO, Cinemax, 
Showtime.) $10.95 +$1.00 postage. Catalog S1.00 
CABLETRONICS, Box 30502R. Bethesda, MD 
20814. 

CABLE television converter, descrambler 
and wireless remote control video equip- 
ment accessories catalog free. CABLE DIS- 
TRIBUTORS UNLIMITED, 11S-P Main Road. 
Washington. AR 71882. 



INVENTORS 



INVENTORS! Can you patent and profit from your 
idea? Call AMERICAN INVENTORS CORPORA- 
TION for free information. Over a decade of service. 
1-(800) 338-5656. In Massachusetts or Canada call 
(413) 568-3753. 



84 



SATELLITE TV 



CABLE TV Secrets — the outlaw publication the ca- 
ble companies tried to bar. HBO, Movie Channel, 
Showtime, descramblers, converters, etc. Sup- 
pliers list included S3. 95. CABLE FACTS, Box 711- 
R, Pataskala, OH 43062. 

SATELLITE TV receiver kits! Instructions! Sche- 
matics! Catalog $1.00 (refundable): XANDI ELEC- 
TRONICS, 8ox 25647. Dept. 21S, Tempe. AZ 
85282. 

DESCRAMBLER build our low cost satellite TV 
video only descrambler lor all major movies and 
sports. Uses all Radio Shack parts. Order P.C. 
board and instructions by sending cheque, money 
order, or Visa for $35.00 U.S. funds to: VALLEY 
MICROWAVE ELECTRONICS, Bear River, Nova 
Scotia, Canada, BOS-1BO. (902) 467-3577 



Mu ti-Channe Microwave T.V. Receivers 



u 

VISA/MC/COD 



t .9-2.7 GHz Parabolic Dish 40-cJBGain 
LIFETIME WARRANTY 

Com pi el e Syslem SB9.95 (Shipping Incl ) 

Replacement Components 

& Expert Repairs Available 

K S S ELECTHDNICS Call now tar same 

P.0.BDX34522 toy sMppinri! 

PHOE MX. A Z BS057 [B02) 230-0641) 

For Dealer Rates Call 602-888-4080 



SATELLITE TV equipment. Buyers guide, discount 
prices. $3.00 N.E.C.S. INC., Box 22808-R1 , Little 
Rock, AR 72221. 

SATELLITE scramble newsletter, non-profit pub- 
lication, descrambler sources, $1.00, MICHAEL 
THOMPSON, Box 4508, Dieppe. Canada, 
E1A-6G1. 

59 degree brand name LNA's! LNB's! Ku-Band 
LNB'slDiscount pricing! Catalog $1.00 (refundable): 
LNA-RE, 201 E. Southern, Suite 100, Tempe, AZ 
85282. 



NEWII INSTALLATION and REPAIR 
of VfdeoCipher* 2000 and 2100 

ThtOnty VCR Jrstmctionaf Video Program 
Demonstrating: 

Normal & Special Installation * Setting External 

Controls • Preforming Internal Adjustments 

• Determing and Repairing Common Board 

Problems * Replacing Parts Cohered by Epoxy 

• Static ft-ecoutions & Special Soldering Techniques. 

Using PHOTIC; the electronic test device for 

the professional TVftO dealer 

Everything you've wanted to know shown 

tor the nrst time, for only 159.95 

S*- pc-ng IS SO Send check crKkltS SO COO EC«»\ certified chec* or WC 
on COO J Hocredrt caret l«*™v PO'I N y add n UK 

TRVO dealers receive SI 0.00 rebate towards 1st 

purchase of PROTEC plus discounts worth more than 

(50.00 on soldering equipment and accessories. 

TESTRON, Inc.. 

ckpt Rl, 184 Jencho luinpikt. Floral Part, N.y 1 1001 

SOO-sai-lOOSot 301 Mhts-7dsys(ir,Nrt5lfr358-94H 



VIDEOCIPHER data disk, Apple II and PC dial 
(011)(52) (451)42268 (Mexico), 4-10 PM. CST. lor 
information. 

SCIENTIFIC Atlantia cable users series 8500 8550 
get all channels instructions for simple modification 
costs under $10.00 to make. Complete instructions. 
Send $10,00 no checks to K.F. SPECIALTIES, PO 
Box 443, Forked River, NJ 08731 , 

SATELLITE systems $295 up. VISA/MC available 
Catalog $2. STARLINK INC., 2603- 6E Artie, 
Hunstville, AL 35805, 

10ft Satellite system, remote controlled, tracker 
and descrambler with 1 yr free subscription to 20 
channels. $1,495 plus UPS, VISTA VISION, 1 (602) 
458-5482 after 10 a.m. 



PRINTED CIRCUIT BOARDS 

CIRCUIT boards prepared from layouts or CAD 
files Call for price list (301) 987-4023. PEL, 1205 
Generals Highway, Crownsville, MD 21032. 



iNUTS&VOLTSi 



O A Z I W 



P.O. Box 11H-6 

Ploeorvtia, CA 32B7D 



GIVE YOURSELF A BREAK — A PRICE BREAK' 
NUTS & VOLTS WILL $tf9 Y'DU MONEY 
□N ELECTRONIC PARTS £ EQUIPMENT 
PM SHOW YOU WHERE TO FIND UN rDUE, 
UNUSUAL AND HAFTDTO FIND ITEMS 



SUBSCRIBE TODAY! 



.*.,:,■., -rj^l.-Hr. 
2r*Glf**M-*<-UIA 
Oil Tim HDH 

T*B tun 11100 

LiUffi.C tW« 



^A t/MtitiutPiiMiatitfl ht Jht ftyi»jAi/jr% QfRtetottitipfynttit 



BUSINESS OPPORTUNITIES 

MECHANICALLY inclined individuals desiring 
ownership of small electronics manufacturing busi- 
ness— without investment. Write: BUSINESSES, 
92-R, Brighton 11th, Brooklyn, NY 11235. 

PROJECTION TV. ..Make $$$s assembling proj- 
ectors... easy... results comparable to $2,500 proj- 
ectors. Total cost less than $30,00, PLANS, 8" 
LENS and dealers information $20.50. Illustrated 
information free. MACROCOMA-GLX, Washington 
Crossing, PA 18977. Creditcard orders 24hrs, (215) 
736-2880. 



ELECTRONIC 
ASSEMBLY BUSINESS 



Start home, spare time. Investment knowledge or 
experience unnecessary. BIG DEMAND assem- 
bling electronic devices Sales handled by profes- 
sionals Unusual business opportunity, 

FREE: Complete illustrated literature 

BARTA. RE-0 Bux 24 B 
Walnut Creel( . Calif. 94597 



HOME assembly. Assemble PC boards for video 
accessories. We supply materials. No experience 
needed, 57.50 per hour. Send self-addressed 
stamped envelope, to: MICRON-ELECTRONICS, 
Box 4716, Akron OH 44310. 

EASY, lucrative. One man CRT rebuilding machin- 
ery. Free info: (815) 459-0666 CRT, 1909 Louise, 
Crystalake, IL 60014. 



GREAT VALUES 'FAST SHIPPING 'QUANTITY DISCOUNTS 

MULTIFUNCTIONAL LED D.P.M. SM " r>15V 2A REGULAT ^n n J 




MEASUREMENT RANGE 
DC. VOLTAGE: ImV - lOOOV 
A.C. VOLTAGE: ImV - 1000V 
DLGITALTHEftMOMETER; (fc 
D.C, CURRENT: 1 uA - 2A 
CAPACITOR METER: 1 pF 




INFRARED REMOTE CONTROL UNIT 

TY-41 MKV 



Kii SSB.50 



m 



as. 



tamed M9.50 



> m ssmjm 



,chti 



J£ 



TO 



fittf 



c<* 



Krt ....... S30.00 

DIMENSIONS: 3 3Mr*n 17/11" x4 1/16" AtuhrrWud with i«t«J ..S36.00 

80W+80W DC LOW TIM PRE-MAIN AMPLIFIER 

TA-SOO . 







KIT .555.30 

METAL CABINET/* FORMER -S3oY$Ho'.BQ 

SUPERIOR ELECTRONIC 
ROULETTE 




TERMS: 510 min order »S20 min chars* care) order "Chc-i:*. money Order or 
uhtiT crticr teeeDiad • We thip 'JPS Ground * Add I OS of TOEil Otdtf ifTiTi 
$3.50 r lor ihippnij. ouindi USA add 20% Imin SS.O0I ■ CA nfkjcnti add 
talei lax • All merchandtw subject to prior sair •Pncrt an rubject Is channt 
bvnh^.jl r.nli-cn * Any ftOQdt urr-veM 1g p«j dflfccUve-, MU&T BE RETURNED 
IN OFtlGlNAL FORM WITH A COPY OF YOUR INVOICE WITHIN 30 
DAVS FOR REPLACEMENT. 



MARK V ELECTRONICS INC.. 



218 EAST MAIN STREET, SUITE 100. 
ALHAMBRA, CA 91801 
TELEX 3716914 MARK 5 



*1* Output voMaqe Ft adiuiiaoie Irom O-i&v DC. two currem ■■ r 

rsngq areavaHjfclrj iw iclcdion; 2COmA of ?A. 
*l* An e^aLtCrilcCS ptoiccvon [ystum il WKially ^ei^rcrt, f 'i3E (Qund 4n d 

& iDo/klmg light wiM tpptir whrn the output i* overloaded 
»I* High icabilrty and reliability if ixmlled by qmployinq high cpiaJiiy 

voltegt regulated IC. 
^ Kino-ifza meter makiesi thfl ne-tfkng « f wfl1l*B* » ni * cu'tent mpre tltirly 

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<fy A r(f mco CIH. mfllfl T anrl all jccesinjy arc cnclatcd lor bOlh kit a" J 

Mumblod form, ll ■* mgil igitebl« far protafwnal or nrneteur dm, 



20 STEPS BAR/DOT AUDIO LEVEL 
DISPLAY KIT ty-45 






That nnw dniQ^ed iMidio level display unO -3 u-img a n£vM 
m cegracvet frtun from Nalional 5»FnicgnductciT lo drive 
20 pieces of color LED'j, \^'rr- vui nv-- and rnd| an each 
channel, it prowidai two- Sycwi of display me-thocfi lar 
telacno-n 'bf' or "doi". The diicle-y rang* n from -57d-H t& 
OdB Kit is nood Iqi any amplHier Iram 1 war.u 10 200W 
• Powar supply requirei 12VAC Or DC. So, 1 ngreai lor 
can a> wail' Kit c&mts Hiih primed circuit board, ail LED 

'f q]«ctrOnic ■: (::-;: ::.-;:'■ :; ::\.\:: 1 >.': and ■■,•.>.•;■:■•-<• (:■ i.!r.' 



011 1 lArJ^ 




[j-n'i-si u-ai Irant panel. 

HIGH QUALITY 
PREAMPLIFIER 
WITH 10 BAND 
EQUALIZER 



.sji.ga 




i<H).0O 



1-800-423-3483 
TOLL FREE 

Onlv for orders paid bv Master or Visa card I 

INCAL: 1-800-521-MARK 



professional' 
color light 
controller 

SM-328 

mm, '"•'""■ipK-rniiS 

OFF.. 
(PACI 
MON. 



INFORMATION: 1-818-282-1196 

MAILORDER: P.O.BOX 6610 

ALHAMBRA, 

CA91802 



to 

09 



CIRCLE 93 ON FREE INFORMATION CARD 



85 



YOUR own radio station! AM, FM, cable. Licensed 
or unlicensed, BROADCASTING, Box 130-F8, Par- 
adise, CA 95967. 

PERSONAL computer owners can earn $1000 to 
$5000 monthly offering simple services part time. 
Free list of 100 services. Write: C.I. L.G.B., P.O. Box 
60369, San Diego, CA 92106-8369. 

EARN thousands with your own electronics busi- 
ness, I do. Fiee proof, information. INDUSTRY, Box 
531, Bronx, NY 10461. 

FLORIDA business lor sale. Electronic service 
sales, FLORI-DAY ELECTRONICS, 44 Avenue E, 
Apalachicola, FL 32320. (904) 653-9657. 

MAKE $$$ manufacturing electronic products! 30 + 

filans $5.00 complete! [Free details available) NRG 
NC, 11580 Oakhurst Rd.. Largo, FL 33544. 

EDUCATION & INSTRUCTION 

FCC Commercial General Radiotelephone li- 
cense. Electronics home study. Fast, inexpensive! 
■Free" details. COMMAND, D-176, Box 2223, San 
Francisco, CA 94126. 

CASSETTE recorded home study for new General 
Class FCC license examinations. Seminars in Phil- 
adelphia, Detroit, Boston, Washington. BOB 
JOHNSON TELECOMMUNICATIONS, 1201 Ninth, 
Manhattan Beach, CA 90266. (213) 379-4461. 



A SINGER'S DREAM! 



WANTED 



INVENTORS! AIM wants— ideas, inventions, new 
products, improvements on existing products. We 
present ideas to manufacturers. Confidentiality 
guaranteed. Call toll free 1-(800) 225-5800 for infor- 
mation kit. 



rf i -V 



REMOVES VOCALS FROM RECORDS! 

How You can sing with the world's best bands! 
The Thompson Vocal Eliminator can remove 
most or virtually all of a lead vocal from a standard 
stereo record and leave the background! 

Write or call For a free brochure and demo record. 

LT Sound, Dept. R-l, P.O. Box 33fe\ 
Stone mountain, GA 30086 (404)493-1258 i 



INVENTIONS, ideas, new products wanted! Indus- 
try presentation/national exposition. Call free 
1-(800) 528-6050. Canada, 1-(800) 528-6060. 
X831 . 

WANTED surplus inventories of ICs, transistors etc. 
No quantity too small or large. Call WESTERN 
TECHNOLOGY, (303) 444-4403. FAX (303) 
444-4473. 



DESCRAMBLER MODULE 

COMPLETE cable-TV decoder in a mini-module. 
Latest technology upgrade for Jerrold SB-3 or Ra- 
dio-Electronics Feb. 1984 project. Available at very- 
low cost. For literature, SOUTHTECH DISTRIBUT- 
ING. 1-(800)-821-5226 ext. 130. 



NOTCH FILERTS 



NOTCH filters for any channel. Send $15.00 for 
sample unit. Specify output channel of converter. 
Money back guarantee. DB ELECTRONICS, P.O. 
Box 8644, Pembroke Pines, FL 33084. 



SCIENTIFIC ATLANTA & SB-3 

SCIENTIFIC Atlanta cable converters (original 
units), models — 8500 and 8550, remote con- 
trol... $240. 00. SB-3 's... $74 .00. TRi-Bi'S.„$95.00. 
SBSA-3'S.. .$99.00. Zenith (Tag-ons)...$159.00. 
Jerrold-450 converters.. .$95.00. Dealer discount 
on units. Call— N.A.S., (213) 631-3552. 



ViDEO TAPE 

f" B S H ■■] COPYGUARD 

Eliminate the latest copyguard problems 

units from $59 9S to $169 es 

'Dthp& 'Ekctronics (714J99S -6S6S 

1 132 Ham ■>%, Otyigt, Co- SZ6&S 



DO IT YOURSELF TV REPAIRS 

NEW...REPAIR ANY TV...EASY. Anyone can do it. 
Write RESEARCH, Rt. 3, Box 601 R, Colville, WA 
99114. 

CABLE TV TURN-ON'S 

"TURN-ON" boards for all models Jerrold 450s, 
Requires no internal modification or soldering, sim- 
ply plugs into existing connector. Fully guaranteed. 
Quantity discounts available. Call or write for infor- 
mation and prices. VIDEO SOLUTIONS, 3938 E. 
Grant, Suite 257, Tucson, AZ 85712. (602) 
323-6072. 

CONSULTING SERVICES 

DIGITEK turns your ideas into hardware. Design 
and/or prototyping. Send SASE for free feasibility 
and cost analysis. No job too small. DIGITEK, Box 
195 Levittown, PA 19059. (215) 949-2260. 

COMPUTERS 

TANDY computers! MSDOS, IBM, compatible. Dis- 
count prices! For quote or purchase call 1-800-36- 
SHACK. EDGEWOOD COMPUTER CENTER. 

CABLE TV D ESCRAMBLERS 
CABLE television converter, deserambier 
and wireless remote control video equip- 
ment accessories catalog free. CABLE DIS- 
TRIBUTORS UNLIMITED, 116-C Main Road, 
Washington, AR 71862. 



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INS2580 3.50 

253QA CPU V» 

2BQB CPU J. 75 

Z80A CTC IJfi 
ZBOA DART 5.25 

280A DMA 5,50 

ZS0APIO 1.95 

230ASI0 *.M 

Z8QB 510 9.85 

I2C43 3.76 

AMDJOOl 4.00 

MH 2.75 

B633 J.fiO 

MOO 1.75 



I09S V:'l I •..-. : i. \--:_, 
n .95 ftoso a oo 



B1M-2 

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073301 12.00 
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82T5 9,00 

1379-5 2.75 

(384 2.M 

B288 4.75 

eifii 12.55 

8748 7.50 

175 MS18450 5.B5 
6.00 TMr5W27NL9.lW 

750 &1000LS 8.60 



RAM 'j 

2018 1 .50 

21L02-3 70 

21QIA-4 1,60 

71 1 IA 1 ,ti 

2112 1 1.95 

51 H? I DO 

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3242 &.0O 

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WMD27 3 .90 

TH5405OWL 1.75 

MMD98-11 1.25 

4TOS.3 1.60 

4115-2 .70 

411(4 1 76 

4184M* JO 

41256-15 3.50 



TRANSISTOR SPECIAL 



M*>fi0Z 
JS104-4 
6118-3 
SH57P.3 



UM14D2 1.75 
t-.'i.i i.in;i i. is 
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ISO 
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INTERFACE 
AV5-10I3A 3,Jfi 
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WM5307 

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hVYH2K 

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SPIN .ID 32 PIN .15 

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IS PIN .15 40 PIN .25 

2D Pin .16 



ROM'l 

INSJflil 4-50 

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835123 1.50 

825120 1 95 

83X129 1.95 

8JSI30 194 

B2S 13* 1 SO 

TPD2&S168 MO 

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743474 3 05 

2?OB 3 .75 

2715 *5V 3.75 

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27128-3D 4.00 

273S8-35 SOO 

™ 3341 A Ufl 

** K2SA3 3.00 

5 3 & 6256* 1.25 



LD65-71W kFt 
LASER diod. 

$ 14.95 



DISC 

Controller* 

DT45C 4 SO 
1771 4,75 

tT-ai a, so 

1 193 9 60 

1795 12.00 

17B7 13.00 

2T97 795 

CRYSTALS 

?OTO 6 144 

3 000 BOOO 

3.579 10.000 

4000 1(000 

5000 16 432 

40*0 20 00O 

1 75 oa, 

NO. 3D 
WIRE WRAP 

.'.I r-:E i.i'jG..- 

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100 H . -Si.« 



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14 PIN .45 Qaop- 4 (0 

16 PIN .50 0898 -% OS 

16 PIN 65 HOODS % 6fi 

20 P-IN .90 DB25P tl.25 

24 PIN ; 11.. D825S 11.50 

29 PIN 1 3fi HOODS* GS 
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100 Jfi 4,0 1.40 
300 ,40 50 1 80 
400 .60 .70 2.40 9.00 
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TRIACi 
PHV 1A IOA 25A 
(TO 36 60 1.40 

200 SO SO 190 

4 00 701.00 2.150 
5001 001 70 J SO 



LINEAR CIRCUITS 



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TTLIC SERIES 



7400 .IS 

MOT . 19 

7402 ,19 

7403 .19 
T*M . IS 
7405 25 
MOfl .27 

7407 77 

7408 34 
7409 
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74(0 .45 

74(3 .60 

7465 .55 

74(0 .35 

7469 1.90 

7490 ,30 



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7416 .25 

7417 .35 
74J0 ,20 
7435 .27 
74-26 .30 

7437 37 
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7438 28 
T440 .20 
7443 .46 
744-5 05 
7448 70 
7460 .20 
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7*73 .35 
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7428 60 



74(1 40 

7482 .50 
7493 .35 

7454 50 

7455 .55 
74(6 .60 
74107 .30 
74115 1.30 
74121 ,30 
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74123 .46 
7*125 45 
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74H60 1.35 
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74156 .76 
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74170150 

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74174 .55 

74175 85 

74176 7! 
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TL062CF 95 
TLDMCH 100 
T1072 1.00 
TL062 90 

TL0S4 1 00 
LH201 75 

LU30I/74 8 35 
LM307 



LM3B7 95 

LM1M 40 

LF338A 3.00 
LF411 125 
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LM310 

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N6fi«3A 1 50 

5D60TO 1 00 

8036 3 85 

B700CJ S.95 

U4130&O 96 



74190 .80 
74131 (a 
74193 75 

74193 ,75 

74194 .80 
74105 SO 

74195 75 
74197 .80 
74199 US 
74221 1.25 
74373 1.00 
74276 1 35 
74270 ,70 
74288 50 
74365 65 
T4307 .66 
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76115 90 
75335 I 50 
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5001 1 00 

5002 80 
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74C931 3.50 


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MS SERIES 

745165 I 50 
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745182 3.00 
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745196 1 30 

745240 1.40 

745241 1 40 
74S344 1 35 
745351 .75 
74S367 90 
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745373 1.65 

745374 1 66 



74LS SERIES 



kSoo 
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74LS02 
74L503 
74LS04 
74LS05 
74L50B 
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74LSIO 
74LSU 
741.512 
74 LSI 3 
74L5I4 
74L515 
74LS20 
74LS21 
74L522 . 
74LS70 
74LS27 
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741,532 
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74t51 

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74L5123 .45 

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741.5135 35 

74LS137 00 

74LJ13B ,30 

74L5139 .19 

74 LSI 45 .70 

74L5147 1.00 

74LS146 JO 

74L5151 39 

74LS15J .39 

74LS154 ISO 

74 LSI 55 ,55 

74L5156 45 

74L51S7 Jfi. 

74 LSI 50 30 

741.5160 29 

74L516I 4fi 

74L5163 49 

74 LSI 53 .40 

74 LSI 54 45 

74 LSI 65 65 

74L5166 05 

74 LSI 60 03 

74 LSI 70 80 

74L5173 49 

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74 LSI 75 38 

74 LSI B l I 40 

74 LSI 90 49 

74 LSI? I 4( 

74L5192 65 

74L5191 85 

74LS104 08 

74L5I35 65 

74LS1SO 55 

74LSK7 .55 

74L532I 55 



PLEASE CALL FOR QUANTITY PRICING 



74L5240 55 

74LS2'! 61 

74L5242 55 

74LS243 65 

74LS244 S5 

74L5245 .75 

74LS240 140 

74L5247 75 

74LS243 bL 

74L525I 45 

74L5253 .45 

74LS257 39 

74L525B 45 

74L82S9 1 20 

74L5260 45 

74L8388 55 

74Lt2^3 T5 

74LS279 .39 

74L82BD t 70 

74L5363 56 

74L52W 80 

74L5393 80 

74L5398 65 

74LS320 7 TO 

74L3J72 500 

74LS323 240 

74L83B5 39 

74L8300 39 

/4LS387 33 

74LS388 33 

74LS373 76 

74LS3^4 76 

741S37T 75 

74LS380 45 

74LS390 1.10 

74LS303 .76 

74L53>98 3 50 

74LS440 2.00 

74LS641 1 40 

7415525 1 75 

74L5H5 9* 

74LS60S 1 45 

74LS670 .95 

S1LS9& 140 



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400 09 25 65 1 50 ioqq 1200 

800 11 30 60 JOO 13 00 15D0 

630 13 35 I 00 250 16(10 1600 

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7400 



Pari Ho. 


1-9 


10. 


Part No. 


1-9 


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7400. . . 


... 29 


.19 


7485. . . . . 


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29 


7490. 


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39 


7106 . . 


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7493. 


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7407 


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74121. . . 


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... .35 


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7410. .... 


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74125. . . . 


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... .75 


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... .45 


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74143. . , . 


, . 4.05 


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7417. . . . . 


. .. .45 


35 


74150. . . . 


... 1.35 


125 


7420. 


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25 


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. . . US 


125 


7430. , . . 


... 35 


25 


74158, . . . 


. . , 159 


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7432, 


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29 


74173. . . 


... .55 


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74174 


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7442. . . . 


... 55 


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74175. . . . 


.. . .B5 


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7445. . , . 


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59 


7446 


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74151. . . . 


. . 1.95 


185 


7447 


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74159. .. 


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1.95 


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74193 . . 


... .79 


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74198. . . 


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39 


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195 


7475. . . 


... .49 


39 


74355 . . 


... 59 


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7475. 


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74367 . . 


... 69 


59 



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74LSOO .. 
74LS02. . , 
74LS04. . . 
74LS05. 
74LS06. .. 
74LS07. . . 
74LSOS-. . 
74LS10. .. 
74LS14. , . 
74LS27 
74LS30. . . 
74LS32. . , 
74LS42 . 
74LS47. . . 
74LS73 . 
74LS74. . . 
74LS75 . . 
74LS76. . . 
74LS85. . 
74LSB6 . . 
74LS90. . . 
74LS93. . 
74LS123. . 
74LS125 . 

'4LSI3S 
74LS1 39. . 
74LS1S4. 
74LS1 57. . 
74LS155. . 
74LS163. . 

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74US166. . 
74LS173. . 
74LS174. . 
74LS175. , 
74LS1 59. . 
74LS191,. 
74LS193. 
74LS221 
74LS240. 
74LS243. . 
74LS244. . 
74LS245, 
74LS259. . 
74LS273 
74LS279. . 
74LS322. 

74LS366 
74LS367. , 
74LS358. . 
74L5373. . 
74LS374. . 
74LS393. . 
74LS59C 
74LS624. . 
74LS629. 
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.49 

.69 



. .79 

. ,79 

. .79 

. .89 

, .99 

. .69 

. .49 

4.05 

. .49 

.49 

.49 

.49 

. .79 

,79 

69 

,6.05 

.2.05 

2.29 

. 1.09 

. 1.09 

109 

2.05 



.79 
.59 
79 
39 
3.95 
39 
39 
39 



.79 
595 

1.95 

2,19 

.99 

.99 
.99 

1.95 



740S/PROIWS* 



74SOO , , 


.. 29 


74S1BS" 


. 129 


74S04 


35 


74S189 


1.69 










74S10. 


29 


74S240 


1.49 


74S32. 


. 35 


745244. 


1.49 


74S74, . . . 


. . .45 


74S253 


79 


74SB5. . .... 


... 1.79 


74S267-. . . 


1.49 


74S86. . . 


35 




1 .49 


74S124 


...2.95 


745373, 


1>*9 






745374, 




745175 . . 


79 


74S472* 


, 295 



74F 











74F04. 


,39 


74F15T. . .... 


55 


74FO& 


.39 


74F193 


3.95 


74F10. . 


39 






74F32. 


.39 


74F244 


139 


74F74. 


49 


74F253. 


.99 


74F8S. 


.59 


74F373 


139 


74F13B. . 


. .eg 


74F374 . 


. V39 



CD— CMOS 



CD4001 


. .19 


CD4076. 


.56 


CD4008 


.89 


CO4081 


25 


CD4Q11 


19 




25 


CD4013 


. ... 29 


CD4093 


35 


CD4016 .... 


29 


CO4094. 


69 


CO4017 


55 


CO40103 


2.49 


CD4016 


59 


CO401 07 


.69 


CD4O20. 


59 


CD40T09. 


1 49 


CQ4024. .., 


.49 




r*t 


CO4027. 


35 


CD4511 


f» 


C04030. 


29 


lT04K?n 


.75 


CO4040. ... 


65 


CD4522. 


79 




. 29 
. ... 29 






CO4050-- 


C04541 


.69 


CO4051 


. .. 58 


CD4543., 


79 


CO4052 


59 


C04563 


4.95 


CD40S3. ... 


.59 


CD4555 


.79 


CD4059 


3.95 


CD4566 


7 49 


CD4063. . .. 


135 


C04S72 |MC 14572J 


39 


CD40&5. . . . 


29 


CD4S83 


B9 


CD4069. 


25 


CD45B4. 


39 


CD4070 


25 


CC4585 


H9 


CD4071. . . . 


2E 


MCI 441 IP. 


im 


CD4Q72 


25 


MC14490F 1 


4.49 



COMMODORE CHIPS 



1NO. 



Pric* Part No. 



WWTODskCgn! «Mi 14.9S 
51-3052P SV ftrWiw 

WBgs fUc !*--., - 595 
6502 MM w.liu. Clack . . . 2.25 

G504ACPJ. 1.95 

6507 ON 445 3.49 

6510 CFU 9UW 

6520 PIA, 1,75 

GS2ZVU 2.95 

6525 TPI *-» 4.95 

652BC1A.. , ..14.95 

6529 SB 445 2.95 

S532 126.4MM. I'D. Tin to 6.49 
S545-1Cfm: 2.49 



Pnc* Part HO. 



6551 ACI*. 321 

S5S0 VK -l 10.95 



. 14.95 

510,95 
.10,95 
.1455 
. 14.95 



6557 WC-ll 

656» vie mm 

6572Vk:PM,N. 
6551 S0II2V), 
6562 513 tfSVJ.. 
6360 1>«l EamnB. .10.95 

8501 MPUl 1055 

6502 WU . . Hi 555 
9593 Ml Cow . 1555 
6564 VIC.. .454512.95 
6S66V1C «L IMS 15.95 
6701 PGck OliB . . . 9.95 
■6721 Put. U5S 



Prtc« 



S722 MWJ 955 

'251 1044)4 Kcms ROM 1055 

3U016413aiKB0M-C138...1S55 
316019413 Buk BOM-CIS! ... 15.95 
31 B020-04 femil ROM -C1 2B. . . 1 5.9 5 
325302^)1 64H RBI to 

1540'I511 Dfnt. 15.95 

-325572.01 Lew *"W. 24 95 

"5ZS100PLA !S»3UQir L . . . . 1355 

901225-01 Chac ROM. 1155 

901 2IW1 BASIC BOM. t1.95 

9OIS27-0J«mim)M. 11.95 

901229-05 ItKiKt ROM 

for I54I >a DlMI 1 5 95 

'No specs available 
"Not&:82S100Pm= U17 LC-841 



MICROPROCESSOR COMPONENTS 



MISCEUANfUUS CHIPS 
Part No. Prieo 



D765AC. . 
WD1 770 ,. . 


4.49 

I'J.OO 14.95 


WD9216 935 6.95 

no, Z30A. I90B semes 

Z80 125 


ZBO-DART. . 
Z80-PI0. . . 


4 95 
1.79 


Z80A-CTC. 
ZSOA-DAFIT 
ZB0A-P1O 

zsOA-siora. 


1.49 

4 95 

1 .49 

495 


ZSOe-CTC 3,49 

2BOB-PI0. 429 

8500/ 6600' 68000 SER 


55C02 (CMOS! . . 6.95 
5520 1.75 






6800 

6802 

6610 


...... 1.75 

149 

125 



G50D/GS0G/6BD0G Cant. 
Part No. PtK* 



6840. 


. ,. . 3.9S 


6B43 


. . . 2.95 






6950 


1.49 


6652 


9i95 2.49 


6675 


,.895 


MO6SO00L8, . 


... 11.95 


t«&flOOOLlO 19S5 1495 


803, BOliO SERIES zg6 


80C3 1 BH . . . 44r95 10.95 


8095, . 


.... 1.49 


8073 


. . 2995 


8080A, 


. . . 249 


808SA. 


.... 229 


8066 


... 695 


80B6-2. 


... 895 


60a7t5MHz).. 


..125.00 


8087-2(8MHzJ 


. . 1 59.95 


8088 


.... 6.49 


&cee-2 ., 


3.95 


8116 


... 4.95 


81 55. 


, . . . 1.95 


61 55-2, 


.... 2.49 






8202 


.... 9.95 


8203. 


. . 14.95 


8212. 


.. .. 1.49 


8224. . 


.... 225 







SDOO SERIES Cant. 
Pert No. Pile* 

8228 249 

5237-5 435 



. 2.25 
. 5.49 
.595 
. 1.75 
1.95 
.495 
. 1.69 
.2-49 



8243. . 

8250A 

S2S0B (For ISMI . 

82S1A. 

8253-5 

8254. 

6255A-5 

8257-5. 

8259-5 

8272 4.49 

6279-5 2.95 

8741 10.95 

674SD (25V) 9J95 

S746H|HMOSJ!2WI..10.9S 

B749. 9.95 

8751 39.95 

8755 , 14.95 

DAT* AC OH is III ON 

ADC0804LCN 319 

ADC0808CCN 5-95 

ADCOB09CCN 3.95 

ADC081 SCCN .... 1 4.9S 

ADCO81 7CCN 895 

QAC0306LCN 1.95 

DAC1 005LCN. 549 

AY-3-1 01 5D 4.95 

AY-5-101 3 A . . &95 2.95 



Part No. 



Function 



' DTMAM1C RAMS ■ 



411S-15 

412S-20 (Piggyback) 

4164-120 

4164-150 

4164-200 

TMS4416-12 

S1 18 

41256-120 

41256-150 

50464-15 

51 1000P-10 

S14256P-10 



15.384 X 1 
131A72 X 1 
65536x1 
65536 X 1 
65536X 1 
16384x4 
16364 x 1 
262.144x1 
262.144x1 
65,536x4 
t, 048576 x 1 
262.144x4 



2016-12 

2102-2L 

2114N 

2114N-2 

2114N-2L 

21C14 

2149 

5101 

61 16LP.2 

6116P3 

6116LP^3 

6264LP-12 

S264H1S 

6264LP-15 

6514 

43256-1 5L 



2048x8 

1024 X 1 

1024 X 4 

1024X4 

1024X4 

1024 X 4 

1024x4 

256x4 

2046x8 

2046x8 

2046x8 

6192x6 

6192x8 

8192 x 8 

1024X4 

32.768 X 8 



(150ns) B9 

(200ns) +49 325 

(1 20ns) 1.75 

(150ns) 1.15 

(200ns) 96 

(I20nsl +es 375 

(120ns) 69 

(120ns), 395 

(1S0nS) USS 2 75 

(ISOns) (4464) 141464) 4.95 

(100ns) 1 Mea 9»95 27.95 

(lOOns) 1 Meg. 4+95 29.95 



1120ns). 169 

(250ns) Lou Ptmer (91L02) 1.95 

(450ns) S3 

(200nfi) 1.03 

(2O0ns) Low Power. 1.49 

(200ns) (CMOS) 49 

(45ns) +95 3.49 

(450ns) CMOS. IBS 

(120ns) Low Ftower CMOS 235 

(150ns) CMOS..... 1.88 

(150ns) Low Fewer. 135 

(120ns) Low Power CMOS. 425 

(150ns) CMOS 359 

(1 50ns) Low Power CMOS- 375 

(350ns) CMOS (LTPD444C) +49 3.95 

(1 50ns) Low Powsr. 2+95 1 7.95 



1702A 

TMS2S16 

TMS2532 

TMS2564 

270S 

TMS2718 

2718 

2716-1 

27C18 

2732 

2732A-20 

2732A-2S 

2732A-4S 

27C32 

2764-20 

2764-25 

2764A-25 

2764-45 

27C64 

27C64-1S 

27128-20 

27128-25 

27128A-25 

27C 128-25 

27256-20 

27256-25 

27C256-25 

27512-25 

68764 

68766 

74S387 

74S47I 

N82S123 



256x6 

2046x8 

4096x8 

8192 X a 

1024x8 

2048x8 

2048 X 8 

2048x8 

2048x8 

4096x6 

4096x8 

4096x8 

4096x8 

4096 x a 

6192x8 

£192 xB 

8192x8 

8192x8 

8192x8 

B192xS 

16384x8 

16384x8 

16364x6 

16364x8 

32.768 x 6 

32.768 x B 

32.766 X B 

55.536 x 6 

8192x8 

8192x8 

256x4 

256x8 

32x6 



- PROHS EPBOMS - 



(1)ffl) .595 

(450ns) 25V. 4.B5 

(450ns) 25V. 5i95 6.95 

(450ns) 25V. BJ95 

C450ns) 436 

(450ns) 3 ^snaas. 9.95 

(450ns). 375 

(350ns) 25V 4.95 

(450ns) 25V (CMOS). 649 

(450ns) 335 

(200ns) 21V. 425 

(250ns) 21V. 3.95 

(450ns) 21V. 3.75 

(450ns) 25V (CMOS) 649 

(200ns) 21V, 425 

(250ns) 21 V. , , 3.78 

[250ns) 12.5V. . . , , 425 

(450na) 21V 3.49 

(450ns) 21V (CMOS) 549 

(150ns) 21V (CMOS) 649 

(ZOOns) 1 2SK 21V. 5,95 

(250ns) 128K21V. 525 

(250ns) 1 25V 435 

(2S0ns) 21 V (CMOS) 535 

(200ns) 256K (125V) 635 

(250ns) 256K (125V). . 595 

(250ns) 256K (CMOS) (125V) 695 

(250ns) 51 2K (1 25V) 19.95 

(450ns) 25V. 15,95 

(350ns) 25V 1695 

PROM O.C 129 

PP.OM TS. 4.95 

PFtOM TS. 2.49 



SATELLITE TV 
PESCRAMBLER CHIP 



Trie MM5321 t5 TV camerij sync generolor ricjigri(H^ Ep 
supply Ihe basic s.ync functions (or titf.tr color or mono- 
CHfomeE25 hnc/GCHi in'lcrljcccl and cd-ti a ra vnk-? recorder 
aprjlKcatlons. COLOfl BURST GATE A SYNC 

allow stable: color Operation 

MM5321N $11.95 

INTERSIL Also Available! 



74HC HI-SPEED CMOS 


PaH No 


P"C* 

25 


PirtNo. 


Price 


74HO0& 


74HC175 


69 


74HC02 


.25 


74HC221 


39 


74HC04 


29 


74HC240. . . 


.79 


74HC08. 


,29 


74HC244 . . 


.79 


74HC10. 


29 


74HC245 . . . 


69 


74MC1 A. 


49 


74HC253 - , 


59 


74HC30. 


29 


74HC259 , . 


. . .85 


74HC32 


29 


74HC273 . . 


.79 


74MC74. 


39 


74HC373, , 


.79 




39 


74HC374. . . 


79 


74HC7& 


.45 


74HC393, . . 


75 


74HCS5 


.79 


74HC595. . . 


, 1.19 


74HC6& 


39 


74HC638. . . 


.79 


74HC123 


.89 


74HC4040, . . 


39 




.49 






74HC132 


,49 


74HC4050 . 


sa 


74HC133, 


49 
.49 


74HO406O. . . 


1 .09 


74HC139. 




1 .29 


741-IC154 


1.19 


74HC4514. . . 


1.19 


74HC163. 


G5 


74HC4536 . 


. . . .69 


7JHC174. 


69 


74HC4543. . 


1.19 


74HCT 


— CI 


TTL 


7 :.<■<: ■:.::' 


29 


-JHC^'39 


59 


74HCT02 


29 


74HGT157. 


69 


74HCT04 


29 


74KCT174 


89 


74HCTDB 


29 


'4HCT175. 


.69 


74HCT10 


29 


74HCT240- . . 


99 


74HCT32 . 


29 


J4HCT244.. . 


.99 


74HCT74 


.49 


74HCTE45 


1.19 


74HCT86 


49 


74H0T373. 


.119 


74HCT13S. . . . 


. .69 


74HCT374. . 


1,19 



7 4 C — CMOS 



74CO0. . . 


29 


74C1 74. . 


. .79 


74C02. 


29 


74C175 


. ... .79 


74O04 


29 


74C221 


..... 1.49 


74COS. 


38 


74C240 


129 


74C10 


35 


74C244 


129 


74C14 


.49 


74C373 


1.49 


74C32 


35 


74C374 


1.49 


74C74. 


59 


74C912 


735 


74C8R 


139 


74C915. 


139 


74C86 


35 


74C920. 


935 


74CS9 


5.19 


74C921 


9.95 


74C90 


-99 


74C922. 


395 


74C1 54. . . 


235 


74C923. 


335 


74C1 73 


1.05 


74C925. 


. . . 5.95 



LINEAR 



DS0026CN 


1 95 


LM 1 «E8N 


39 










TL.034CN. 


. .99 


DS1 4C83N (CMOS) 


1.19 










LM307M. 


45 


DS14C89NICMOS) 


1.19 


LM309K. 


1 J5 


LM1496N 


.85 


LM311N 


. .45 


MC164BP. 


491 


LM317T. 


. ,79 


LM1871N 


2.95 


LM318N 


. .99 


LM1672N 


2.95 


LM319M..., 


. 39 


LM1896N-1 


1.59 


LM323K. 


.3.95 


ULN2003A 


.99 


LM324M 


. .39 


XR2205 


3.95 


LM33BK. 


.4 95 


XR2211 


?«* 


LM339N 


. 39 


XR2243. 


195 


LF347N 


. 1.79 


DS26LS29CN 


4,49 


LM348N 


.69 


DS25LS31CN. 


1 19 


LM35OT. 


.2.95 


DS26LS32CN 


1 19 


LF351N 


. 39 


□S26LS33CN 


1 cp, 


LF353N. 


49 


LM2901 N 


.49 


LF355N 


. .79 


LM2907M 


Z49 


LF356N 


. .79 


LM2917N (8 plnl. 


155 


LF357N. 


. 1 09 


MC3419CL. 


H95 


LM358M. 


. .49 


MC3446N 


238 


LM3S0M 


.2.19 


MC3450P. 


?9S 


LM361N. 


. 1.79 


MC3470P. 


1.96 


LM380N-8. 


99 


MC3471P 


4<P> 


LM38BN-3. 


. 39 


MC3479P. - 


4.79 


LM387M 


. .99 


MC34S6P. . 


1j69 


LM393N 


. 39 


MC3437P. 


1.69 


LM399H 


.2.95 


LM3900N 


49 


LF411CN 




LM3905P* 


1.19 


TL497ACK 


.2,69 


LM3909N 


■» 


NE540H (C540H) . 

ME555V 

XR-L555 

LM556K. 

ME5SBM 

LM555N. 


..2.95 
29 
.75 
.49 

69 
. . .99 


LM3914M. 

LM3916M 

NE5532 

NES534 

7805K (LM340K-5) . 
7812K (LM340K-12) 


1.95 
1.95 
.59 
.69 
. 129 
.129 


781SK (LM340K-151 


129 


NE592N- 


. 39 


7805T (LM340T-5) 


. 49 


7812T(LM340T.12J 


. .49 






7815T(LM340T-15! 


49 




- 59 


7905K (LM32DK-5I 


1 ftfl 


MC1350, 


. 1.49 


7905T (LM32QT-5) 


. 59 


MC1372P. 


.2.49 


75472. 


39 


MC1377P, 


319 














LM1414N. 




MC145406P. 


2.95 



IC SOCKETS 



Law Pro fife 
SpriLR 11 

14 pin LP. 12 

16 pin LP. 13 

24 pin LP, .25 

2B pin LP. 27 

40 pin UP- 59 

SoMHUH£l*M*nl [Geld *THl| i 



Win Wrap (Guidi ■.***! *3 

S pn WW. . 59 

14 pin WW. £5 

16 pin WW.. .68 

24 pin WW. 1.19 

28 pin WW 159 

40pin WW. 1.H9 



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ELECTRONICS 



COMMODORE COMPATIBLE 
ACCESSORIES 




HESWARE 300 Baud Modem 

FOR VIC-20 AND C-64 
Connects directly to User Port - Manual Answer/ 
>ial ■ Function keys defined for convenience 
' Includes Midwest Micro Associates communi- 
cation software. 

SM-1 IForUIC-id.niiC-et) $8*795 $19.95 

External Power Supplies 

~PS-1 (r.. c-s4j: $39.95 

3PS-1 28 (f« c-1281 $59,95 

RS232 Interface 

Allows connection of standard serial devices. 
JE232CM (Ftorvic-M„c-64*c-i2aj . . $39.95 

"Opflranon wilh "he C-1 2-8 in S4 mode only 

l-RS-80/TANDY COMPATIBLE 
ACCESSORIES 

E-X-P-A-N-D TRS-80 MEMORY 

Alt kits come complete with documentation 

TRS-30 MODEL 4, 4P, &4D 64K/12BK EXPANSION 

TBS-64K-2 57.95 

expands Model t from 1 6K-6JK or Model 4 tGatc Array 
Atrsion). 4P and 4D From 64K-12IK 

rFtS-64K-2FWL , 91*95 S13.9S 

=xoands Modal 4 (Non-Gate Array version] rrom 64K1o 12flK 

rBS-80 MODEL 100 8K EXRUISIDH 

M1008K MftW 517.95 

ZUCKI=RI3C^RD 

I, SflDBi TANDY 1000 

Expansion Memory 
Half Card 

Expand the memory ol your 
Tandy 1000 (12SK Version) to 
as much as S40K. Also includes 
DMA comrolter chip. 

TAN-EM256K Includes 256K RAM $ 99.95 

TAN-EM512K Includes 51 2K RAM $1 19.95 

TAN-C Pfug-inCfock option cnip (only) $39.95 

NEW.' 20Meg Hard Disk NEW! 

T20MB 20MB Han.: Disk Drive Board 

for Tandy 1 000. . 957 9 . 9 5 $494.95 

SX20MB 20 M8 Hard Disk Drive Board 

for Tandy 1CCCSX 6509. 9 5 5499.95 

TANDY 1000 

Multifunction 

Board with 
Clock Calendar 

Expand the memory on your Tondy 1 000 ( 1 28K version) to a s 
much as 640K. Complete win an RS232 port. clock/calendar. 
HAM Disk Prinlef Spooter andon-Ooard DMA controller chip. 

MTAN-256K Includes 256K FIAM. $1 79.95 

MTAN-512K Includes 512KHAM $199.95 

NEW! Multifunction NEW! 

Board for TANDY 1000SX 
M256K includes 256k ram $1 89-95 

UV-EPROM ERASER 








Erases sll EpflOMs. Erases up to 8 chips within 21 mlnules 
(1 etiip in 1 5 minuure) . Maintains constant exposure distance 
ol t u . Special conductive loam liner eliminates static build-up. 
Built-in safety fock to prevent UV exposure. Compact - 9.001. 
x 3.70'W x 2 fi'O'H. Complete with holdino tray for 8 chips 

DE-4 UV-EPROM Eraser. . . . $69.95 

UVS-11EL Replacement Bulb. ... $19.95 
NCF-2 Cond.Foam12x24x<JiHardBlk. S 8,95 




HOW YOU CAN BUILD AN IBM PC/XT COMPATIBLE! 
Jameco's IBM PC/XT Compatible Kit 

4164-150 1 2£K RAM ( 1 a Ch Ips) $20.70 

IBM-FCC nappy Csnlrallw Card . . $34.95 

IBM-Case n.p- Top case $34.95 

J-JE1 015 XT.-'AT Style Keyboard . - - $59-95 

lr ""» 150 Watt Powar Supply.. S69.95 

MonorGrapti, Crd. w/RPort S69.9 5 

51V DSDD Disk Drive $99.95 

12' Mono. Green Monitor $99.95 
XT Motherboard CZero-K f:. .'.' ■■■-. 
DTK/ERSO 6fDS ROM) $99 95 

FREE! QUICKSOFT PC 
WRITE WORD PROCESSING 
SOFTWARE INCLUDED! 
Weight: 48 lbs. Regular List $590.30 
JE1004 (Includes 9 items above) . . . . . $499.95 
ADDITIONAL ADD-ONS AVAILABLE! 

RS232HC RS232 Serial Half Card $ 29.95 

EM-100 6 x 1 1 a n « i 01 1 M !> mo r v H .1 If Ca r rl ( Wl tlr lit R AM) , , S 59.95 

JE1052 Integrated Color Graphics Board $ 59.95 

JE1078 Multifunction 0-384K RAM (without RAM) $ 89.95 

PM1200B-2 I200/300 <!l:iii -,1H,.ir( :.it:l I.'.-- ■!■ m Wl !li ■■■ .ftwHO, . . $119.95 

PM1200B-2S 1200/300 Baud Harf Curd Modem with Mirror Software. . S149.95 

JE1 055 Enhanced Graphics 25EK Video RAM $1 99.95 

TTX-1410 14 » RGB Color Monitor $289.95 

ST225K 20MB Hard Disk Drive, Controller S Cable $339.95 

fiUisi reoisrerep trademark of !8M Computers 




NEW.' Logitech Mice $4££y 

IBM PC/XT Compatible 

C7BA5E C7 Mouse wrth 3.1 Software SB 4.9 5 

C7PLUS C7 Mouse wrPLUS Pko, SoKwaie $94.95 

C7BUS C7 Mpuae wrBua Brd. ft PIUS Ptqj . Sfwr. $109.95 




IBM PC/XT/AT 

Compatible 

Keyboard 

n** , F tyte 

l* Lavot 








a 



Layout 



■ Tactile touch keyswitches ■- AT style layout ■ Switch selectable between PC/XT 
or AT ■ Illuminated Caps Lock. Num Lock and Scroll Lock indicators ■ Low 
profile design ■ S 1 ^ loot cord - Manual included ■ Size: 1S"L x 7VW x IVaTH 

JE1015 $59.95 



IBM PC/XT 
Compatible 
Enhanced 
Keyboard 




f r I I U;,* iJt.t n f 1 sufcfci scorn 
.. it: i i.Mi *•- i 



111. I I L—-I ' \ vu 



•Enhanced PC/XT keyboard (equiv. to Keylronics 1 * 5151) ■ Separate cursor 
and numeric keyboard ■ Typewriter style: layout makes it easier |g learn! ■ LEO 
indicators ■ Manual included ■ Color: off-white * Size: 20"L x BVYV x 1 VH 

JE1016 $79.95 

Turbo 4.77/8MHz Motherboard 

IBM PC/XT Compatible 

•75% faster than the IBM PC while in 

the turbo mode ■ Turbo Mode selectable 
through either software or hardware 

• Expandable to 640K (comes w/zero-K) 

• DTK/ERSO BIOS included 

TURBO SALE! $120.05 $119.95 




APPLE COMPATIBLE 
ACCESSORIES 

Parallel Printer Card 
■aj".3Ti?ir.a for Apple II, IH- and lie 

■ Intelligent interlace to 
moat dot matrix graphics 
printers 

■ Centronics standard 
- Advanced text printing 

Parallel printer Card $49.95 

54K Buffer for JE880 $0 9 . 9 5 $49.95 

JE8B03 jEasoeno-jeaaa $9935 $89.95 
Extended 80-Column 




JE880 
JE883 




Card for Apple We 



• ao Csl.'G4K BAM ■ Doubles 
amount ol data your Appro tie 
can display as well as its mem- 
ory capacity ■ Ideal for word 
processing ■ Complete with 
instructions 

JE864 $59.95 



Additional Apple Compatible 

Products Available 



Iameco 
ldtJ.l.:r.rtM.-i 




JE310 Fiber Optics 
Experimenter Kit 

JUrcu/t/ ' Educational device 
iWWI rjjvea '■: i. :■'.■■-■. and 
engtirtGera hands-orr 
experience with fiber 
optic technology 
9 Step by &tep In- 
slruclL-una ■ Includes 
transmitted A racaiver 
cir-cuits mjards, as, 
well as el| nee. iC'a, 

CJlbEas 3 curr. u-iau -i 
JE31 Fb*r Optic Kit. $1 9.95 



am&CA JE450 Sotderless 
B i "j!5fiai Proto-Type Builder 

■ Provides user wilh quick 

and efficient system for 
bread boarding electronic 
circuits ■ Components & 
wire leads can be quickly 
inserted and removed 
without soldering or de- 
soldering ■ 3 regulated 
power supplies: 5V @ 1 A, 
-t-5Vto +15V& .5A, -SV 
to -15V @ 5A -Power: 
1 20VAC, 60Hz (used 



J 




new-' 

JE450 Solrfertess Proto- type Builder . , - S 1 1 9.95 



5" /S4 




IBM 
9 Compatible! 
DISK DRIVES 

trtotudmi 
FD55B HhW ds i 4 -h fjBM pc/xt) . .. $109.95 

JU-455 Pina5OTic5^DS^-H([BHPC/XT) $109,95 

JU-475 Psnasonic s^ 1 os tt-H (IBM AT) . . $1 29.95 

DATA BOOKS 

'30003 NaEicnal Linear data Book \82} $14.95 

30009 Ink-nil Data Book (SG.I » . $ 9-95 

30013 ZJlog Data Book (AS} S14.9S 

30032 NatiunaE Linear Suppl*menl[84) £ €,95 

210830 Intel Memory Handbook (87) S17-95 

230343 Intel Microsystem Hndbk. Sel (ST) $24,95 

MUFFIN/SPRITE-STYLE FANS 



MUF60 S9.9S 

Torin Industries (4.6fl" sq.. 60 ctm] 

SU2A1 58.95 

EG10 flotron 13.155" square. 20 cfm| 




$20 Minimum Order - U.S. Funds Only 
Shipping: Add 5% plus S1 .50 Insurance 



Send $1.00 Postage for a 
FREE Seasonal Flyer 

FAX 415-592-2503 

8/87 




California Residents: Add 6%, 6 1 / 2 % or 7% Sales Tax 
We reserve the right to substitute manufacturers. 

® 



Mall Order EJGcl rflniCS ■ Worldwide 



ameco 



ELECTRONICS 



VISA* 



Data Sheets - 50c each 
Prices Subject to Change 

Send $1.00 Postage for a 
FREE 1987 CATALOG 

Telex: 176043 

019S7 Jameeo Electronics 



1355 SHOREWAY RD., BELMONT, CA 94002 • FOR ORDERS ONLY 415-592-8097 • ALL OTHER INQUIRIES 415-592-8121 



CIRCLE 1 14 ON FREE INFORMATION CARD 



r 



Computer Power Command 
Center for only $39.95! 
At this price they won't last 
long, so order yours today! 



v 




This superb monitor stand puts control 
of your entire system at your fingertips! 
Our special purchase of these units 
can put one in your hands at 
an unbeatable price! 



TILT & SWIVEL POWER COMMAND 

*39 95 

X-1128 



Get rid of that confusing maze of wires and ease 
operator fatigue with this one fantastic product! 
The monitor stand swivels 360° and tilts 12.5° to 
improve line of sight and minimize glare. The 
electronics built into the base provide EMI filtering 
and surge & spike protection for five component 
inputs. You can plug your computer, monitor, 
printer, and two other devices into the 3-pin 
sockets in the back of the stand and control them 
individually with the lighted rocker switches on 
the front Or rum the entire system on and off with 
the master control switch! 



SIZE: 11 WW x tQWD i3K"H 
WEIGHT: 4 lbs. 

POWER CORD: 54" 1 4 AWG > 3C 
CIRCUIT BREAKER: 1 5 Amp 



Compare 
Our Price! 



Dealer Inquiries welcome! Just circle reader service number 189 










o 

DC 



o 

UJ 



o 
5 
< 



20 MHz Dual Trace Scope Price Breakthrough! 




was $399 - 



SAVE $80 now 



Includes quality probes (xl,xl0,gnd) 

Built-in component tester 

TV- video sync (liter 

X - Y operation 

Z-axis (intensity modulation) 

1 yeat wartanty 



$319' 



SPECIFICATIONS 



15 MHz 

PORTABLE 

DUAL TRACE 



20 MHz 
DUAL TRACE 



35 MHz 
DUAL TRACE 



SO MHz 
DUAL TRACE 




Rise lime | usee} 


24 


<17.S <10 


<7.7 


Mix input 




600 V p-p or 300V | DC ± peek AC] 




Input Impedance 




1 M ohms shunted by 20pF ± 3pF for all models 




Chop frequency 




200 KHz (appro*] for all models 




Channel separation 


eotse 6 i khi 


60dBO 1 KH; 60dB @ IKHi 


70dB @> 1 KKi 


Time base 


.5 usee ■ .5sec 


.2 usee to .5 sec .1 usee -. 5 sec 


2 usee - .5 sec 


CRT 


95 mm 


5" 5" 


5" 


Cat No, 


0-1 Z44 


0-1240 Q-1241 


0-1243 



Versatile prob* suits virtual lv any'scope. It features built « al/xlO 
switch. 4' of SHIELDED cable with FJNC connector, and wandering 
earth lead with alligator clip, insulting, shroud. 

Spscrtlcotiorij Working voltage - &G0V FA {or 600V 0Q# Bandwidth - 
xl: DC-10MHi/ztO: DC-l0OMHi« input r^sslonce -*1 IMohnv'xTO: 
10M ohm • Input capacitance -xl : 40pF ±CKQ input e/xlO: 10- 
60pF • HEF position -probe groundad wta 9M resistor. 



NOW 

SAVINGS 



$349 
$150 



$3t9 

$80 



$449 
$150 



$649 

$250 



All "scopes are supplied with schematics 



90 



14-Day Satisfaction Guarantee 



MAIL ORDERS 

DSE, P.O. BOX 8021, Redwood City, CA 94063 

We ship UPS Ground unless otherwise requested Add 5% of order total j-mm 
S1.50I for shipping Outside USA add 20% (mm $4) Thete 15 an additional 
Si 50 handlmg fee California residents please add sales tan VISA and 

MASTERCARD welcome. Minimum order value $20,00 



PttMt* Not*; Stfe flflttt *rt MfmifMbft by MAIL ORDER ONLY. You 
musi irjru rion this »d mnd quote Ihe pricwl On Him ttwmj you wttt, otfmr vmiid 

through July 3 J. 1*87 or whjlt mttpptfct last ■ qutnUlims art ftmitad, so 
hurry? 

ELECTRONICS 

Stores m Hf RK£ tf V. CA 14 1 5/ 4BS-0 755. flf 0W00D CITY. CA I* IS) 368-88*4. SAN JOSE CA 14081 2* 1-2266 

To receive your copy of our Colorful 148 page catalog, circle Reader Service 130 



Order by Phone 
41 5-368-1 066 



Mon - Fri 7am - 6pm 
Pacific Time 



Here is just a 
sample of what 
you'll find at 
MCM Electronics 




Tenma Soldering Station 

■ Adjustable temperature range of 150M2u°C (300' 
790° F} ■ Grounded tip tor soldering static sensitive 
devices ■ Overheat protection with closed loop 
temperature control ■ Replaceable iron clad tip 

■ Improved circuit design for greater temperature 
stability 



Deluxe Anti-Static Oesoldering Tool 

■ Rugged metal construction ■Anti- 
static lip ■ Nozzle cleaner 

■ Lightweight and compact 

■ Disassembles easily for cleaning 

■ 7¥«" long x %" diameter 




1 15MHz Dual Trace Portable 
Oscilloscope 

■ Dual trace model capable of 

displaying signals up to 15MHz, 
for up to two hours on a single 
charge of its internal battery 

■ Power can be supplied from 
either a 12VDC or 120/240V 
5O/60HZ AC source 



Tenma 10 Amp Regulated Power Supply 

■ Output: Regulated 13.8VDC ■ Input: 1 2D VAC ■ Fuse 

protected ■With easily accessible fuse holder ■ Neon light 
indicator ■ Heavy duty binding posts ■ Effective beat sinks 
for more power dissipation ■ Output current: 10 amp one 

minute on. three minutes off; 7 amp continuous 

Tenma LCR Meter 

■ LCR Meter provides a convenient way to accurately 
measure inductance, capacitance and resistance (.01 ohm 
resolution) on its 314 digit LCD display 



For more specs and Test Equipment see pages 
146-154 of Catalog #15 



Anti-Static Work Mat 

■ A must for the modem service shop. 

■ Use in conjunction with our 
#21-660 wrist strap to help 
eliminate static related problems 

■ 18" x 26" 

Anti-Slatic Wrist Strap 

■ This wrist strap when used with our 
anti-static work mat, will effectively 
dissipate static charges ■ The five foot 
coiled, cord with 1Mohm resistor, 
snaps to wrist strap to give user added 
mobility ■ Cord is terminated with a 
banana plug and alligator clip 



For complete information see 
page 136 of Catalog #15 



Be Sure To Call For 
Your FREE Catalog! 
Over 7,000 Items! 
Call Toll Free 1 -800-543-4330 



Additional Soldering Equipment can be found 
on pages 137 and 138 of Catalog #15 



Super Wash 

■ Powerful spray cleans intricate electronic assembly without 
harming plastics ■ Dries instantly ■ Spray literally blasts dirt 
and grease away ■ 24 oz. 



Tuner Cleaner 

■ Cleans, lubricates, protects ■ Cleans and restores dirty and 

corroded contacts ■ Doesn't harm plastics ■ 16 oz. 



Wire Stripper and Cutter 

■ Made of tempered steel ■ Adjustment can be 
sel for wire sizes 10-24 gauge ■ Return spring 

■ Cushion grip ■ 5M" long 




For more Chemicals and 
Tools see pages 128-136 of 
Catalog #15 



Diskette Pile Box 

■ Stores up to 70 — 514" diskettes t Case made 
of anti-static ABS plastic with smoked acrylic 
cover ■ Six adjustable index dividers 

Deluxe Joystick for Atari and Commodore 

■ For use with Atari, Commodore and other 
VCS compatible systems* Two firing buttons 

cord with 9 pin plug 



Catalog #15 has other Computer Equipment 
and Accessories on pages 119-127 



SoS 



© 1987, MCM Electronics 

MCM ELECTRONICS 

858 E. CONGRESS PARK DR. 
CENTERVILLE, OH 45459 

A PREMIER Company 



> 

c 
o 

c 

07 



In Ohio 1-800-762-4315 

In Alaska and Hawaii 1-800-858-1849 



CIRCLE 87 ON FREE INFORMATION CARD 



SOURCE CODE: RE-35 



91 



1200B MODEM $9095 «««•■' 2400B MODEM $19995 



2101 
SI 01 
2102 L-4 
2112 
2114 

::i i.-.i •; 

2114L-2 

2114L-1S 

TMS4044-4 

TMM2015-150 

TMM201S-100 

HM6116 : 

HM61163 

HM6116LP-4 

HM6116LP-3 

HM6116LP-2 

HM6264P IS 

HM62B4LP-1S 

HMS2B4LP-12 



I i 1 L.IW [lov.nr 



256x4 
256x4 
1024x1 
258»4 

1024x4 
1024x4 
1024x4 
1024.4 
4096*1 
2043x3 
204 S xS 
2043x3 
2048x8 
2048x6 

204 a xa 

2048.3 
8192x6 
81 92x8 
6192xS 



I450na) 
BSOneHCMOS] 

MStlri-.liUI'i 

1450.15! 

|450na) 

BSOnaliLPI 

<200nIKI.PI 

1 150..5I 1 1 P! 

(450ni| 

1150ml 

(100ne| 

T200nsl[CMO5| 

[150n«HCMOS| 

[200ml [CM OS Ml PI 

l150m)[CMOS)[LP| 

(1Z0ml(CWOSI[LP) 

HMnWCMOSi 

(150n«](CMOS)(LP) 
(120n»](CMO5)(LP) 



1.95 
3.95 

.93 
2.99 

.99 
1.09 
1.49 
1.95 
1.95 
1.49 
1.95 
1.89 
t.95 
1.95 
2.05 
2.95 
3.89 
3 95 
4.49 



DYNAMIC RAMS 



4116-250 

4116-200 
411S-150 
4116 120 
MK4332 
J164-200 
41 6-1-1 50 
41 64-1 20 
MCM6665 
TMS4164 



16384x1 
16384x1 
16384x1 
16384x1 
32758,1 
05536x1 
65536x1 
85536x1 
66535x1 
65535x1 



4164- REFRESH 65536x1 



5v= Single S Volt Supply 



9035 


1.49 


9039 


1.95 


6080 


2.95 


BOSS 


2.49 


6087-2 


169.95 


8067 


129.00 


8038 


6.95 


80BB-2 


9.95 


81 5S 


2.49 


8155 2 


3.95 


874S 


7.95 


8755 


14.95 


80ZS6 


129.95 


S0Z97 


199.95 



8200 




9203 


24.95 


9205 


3.29 


9212 


1.49 


9216 


1.49 


9224 


2.25 


6237 


4.95 


8237-5 


5.49 


8250 


6.95 


9251 


1.69 


9251 A 


1 89 


B2S3 


1.69 


8253-5 


1.95 


B2SS 


1.63 


9255-5 


1.89 


9259 


1.95 


3259-5 


2 2 


9272 


4.95 


9279 


2.49 


9279-5 


2.95 


9282 


3.95 


92S4 


2.95 


9286 


395 


19288 


4.95 



z-ao 




ZSO-CPU 2BMHje1.69 1 


4.0 MHZ 


ZSOA-CPU 


1.79 


ZSOA-CTC 


1.89 


ZBOA-DART 


5.95 


2SOA-DHA 


5.95 


ZSOA-PtO 


1.89 


7.S0A-S1O/0 


5.95 


ZBOA-SIO/1 


5.95 


ZBOA-SIO/2 


5 95 


6.0 MHZ 


zeoB cpu 


3.75 1 


Z80B-CTC 


425 


Z80BPIO 


4 25 1 


ZSOB DART 


14.95 1 


2808 S1O/0 


12.95 1 


2806 SI 2 


12.95 1 


Z8G71 ZILOQ 


19-95 J 



(250m) 
|200m) 

.I50nsl 
(120ml 
1200m) 
1200m 1(5 «l 
(150m 1(5*1 
(120ml(5v) 
(200mll5vj 
(150m|(Sv) 

(ISOnallSVHREFHESHI 
|150ml[5vl 
IISUiis-.lSvl 
i1SU.iij.5vi 
(200m||5v) 
[15Qns)(Sv| 
REFHESH.PLn 1 Raff. 



.99 
99 
1.49 
6.9S 
1.19 
1.29 
1.95 
1.95 
1.95 
2.95 
4.95 
5.95 
6.95 
2.95 
Z.95 
■■h 



• **• HIGH-TECH ••••' 

NEGV20 UP07010B $1195 

REPLACES 8080 TO SPEED UP IBM PC 10-40% 

* HIGH-SPEED ADDRESS CALCULATION 
IN HARDWARE 

* PIN COMPATIBLE WITH 8088 

* SUPERSET OF 8088 INSTRUCTION SET 

* LOW POWER CMOS 

8MHZ V20 UPD70108-8 $13.95 
8MHZ V30 UPD70116-8 $19.95 

• ••• SPOTLIGHT • ••• 



ORDER TOLL FREE 

800-538-5000 





EPROMS 




2708 


1024*9 


(450ml 


4.95 


2716 


2043x8 


(450nj)(5V) 


3.49 


2716-1 


2048x9 


(350 nil (5 VI 


3.9b 


TMS2532 


4096x8 


1450m) |S V) 


S.95 


2732 


4096a9 


(450n«](5V) 


3. 95 


2732A 


4096x9 


(250m)(5VM21VPGM 


3.95 


2732A-2 


4096x9 


(200m)(5VII21V PGM 


4.25 


27C64 


81 92x6 


(250m)|5V|(CHOSI 


5.95 


2764 


8192x9 


(450m) ( 5 V). 


3.49 


2764.250 


81 92x9 


(250m](5V) 


3.9S 


2764-200 


8192x9 


(200m) ISV) 


4.25 


MCM68766 


8192x9 


(350m)(5V)(24 PIN) 


17.96 


27128 


16994x8 


(250m)(6«) 


4.Z5 


27C2S8 


32769x3 


|250m)l5V)(CHOSI 


10.95 


27256 


3276SxB 


(2S0m)|5V) 


7.49 


5V. Single 5 


'-'■ .Ir Supply 


21V PGM.Progrim M 21 VoftiJ 



DSPECTRONICS 
CORPORATION 



EPROM ERASERS 




CRT 




CONTROLLER 


8645 


4.95 


68B4S 


B.95 


6847 


11.95 


HD 46505 SP 


6.95 


MCI 372 


2.95 


8275 


26.95 


7220 


19.95 


CRTS027 


12.95 


CRT5037 


9.95 


.TMS9918A 


19.95 J 



DISK 




CONTROLLER 


1771 


4.95 


1791 


9.95 


1793 


9.95 


1795 


12.95 


! 1797 


12.95 


2791 


19.95 


1 2793 


19.95 


2797 


29.95 


6843 


19.95 


8272 


4.95 


UPD765 


4.95 


MR8876 


12.95 


MBBS77 


12.95 


1 1691 


6.95 


12143 


6.95 



8501 




1.0MHZ 


6502 


2 69 


65C02ICMOS1 12.95 I 


6507 


9.95 


6520 


1.95 


6522 


4.95 


6526 


26.95 


6532 


6-95 


654S 


6.95 


6551 


5.95 


6561 


19.95 


6591 


34.95 


2.0 MHZ 


6502A 


2.95 


B520A 


2.95 


E522A 


5.95 


5532A 


11.96 


6545A 


7.95 


6551 A 


E.95 


3,0 MHZ 


L 6502B 


6.95 J 



BIT RATE 

GENERATORS 



[ UARTS 




AY5-1013 


3.95 


AY3-1015 


4.95 


TH1602 


3.95 


2651 


4.95 


IM64Q2 


695 


IM6403 


9.95 


1 INSB250 


6.95 J 



BBOO 1 


1.0 MHZ 


6900 


1.95 


6902 


4.95 


6803 


9.95 


6809 


5. 95 


6809E 


5.95 


MM 


1.95 


6920 


2.95 


6921 


1 95 


6840 


6.9S 


6843 


19.95 


6944 


12.95 


6S45 


4.95 


6847 


11-95 


5850 


1.95 


6883 


22.95 


2.0 MHZ 


6SB00 


4.95 


6SB02 


5.95 


68809 E 


6.95 


6SB09 


6.95 


68BZ1 


3.95 


68845 


6.95 


68BS0 


2.95 


6SB54 


7.9S J 



SOUND CHIPS 

76477 5-95 

764B9 a. 9 5 

SSI -26 3 39.95 

AV38910 12.95 

AY3S912 12.95 

. SP1000 39.00 , 



' CRYSTALS ' 


. 32.769 KHi 


.95 


1.0 MHz 


2.95 


1.8432 


2.95 


2.0 


1.95 


2.097152 


1.95 


1 2.4576 


1.95 


3 2703 


1.95 


3.S79545 


1.95 


4.0 


1.95 


4.032 


1.95 


5.0 


1.95 


5.06 BB 


1.95 


6.0 


1-95 


6.144 


1.95 


6.5536 


1.95 


8.0 


1.95 


10.0 


1.95 


10.73B635 


1.95 


12.0 


1.95 


14.31618 


1.95 


1S.0 


1.95 


! 18.0 


1-95 


17.430 


1.95 


18.0 


1.95 


18.432 


1.95 


20.0 


1.95 


22.1184 


1.95 


24.0 


1.95 


32.0 


1.95 


CRYSTAL 


OSCILLATORS I 


I.OMHi 


5.95 


1.8432 


5.95 


2.0 


5.95 


2.4576 


5.95 


2-5 


4.95 


4.0 


4.95 


5.0688 


4.95 


E.O 


4.95 


6.144 


4.95 


8.0 


4.95 


10.0 


4.95 


12.0 


495 


12.480 


4.95 


15.0 


4.95 


16 


4.95 


19.432 


4.95 


20.0 


4.95 


.24.0 


4 95 J 



CLOCK 

CIRCUITS 

MM5369 1.95 

MM5369-EST 1.95 
MM58167 12.95 
MM 5 a 17-! 11.95 
[ MSM5832 2.95 



r misc 




TMS99531 


9 95 


TMS99532 


19.95 


ULN2003 


.79 


3242 


7 95 


3341 


4 95 


MC3470 


1.95 


MC3480 


8.95 


MC3467 


2.95 


11C90 


19.95 


2513-001 up 


6.95 


AV 5-2376 


11.95 


l AY5-3600PB0 11.95 



Model 


Timer 


Capacity 
Chip 


Intensity 
(uW/Cm") 


Unit 
Price 


PE-14 


NO 


9 


8,000 


S83.00 


PE 141 


VES 


■ 


8.000 


*1 19.00 


PE-24T 


YES 


12 


9. BOO 


SI75.0O 
















HIGHSPEED CMOS 

A now family o1 high speed CMOS logic featuring 
I he speed ol low power Sehottxy [6ns typical gala 
propagation delay), combined with the advantages of 
CMOS- vetv law power consumption, superior noise 
immunity, and imnrcyod output dnve. 



74HC: Operate ai CMOS 
To* new. all-CMOS designi, 
74HC00 .S3 

74HC02 .59 

74HC04 ,59 

74HC0S .59 

74HC10 .59 

74HC14 .79 

74HC20 
74HC27 
74HC30 
74HC32 
74HC51 
74HC74 
74HC95 
74HC85 
74HC93 
MHCI07 
74HC109 
74HC112 
74HC125 
74HC132 
74HC133 
74HC138 
74HC139 



logic levels and are ideal 



.59 
.59 
.59 
.69 
.59 
.75 

1.35 
.69 

1.19 



74HC14B 

74HC151 

74HC154 

74HC157 

74HC15S 

74HC163 

74HC175 

74HC240 

74HC244 

74HC24S 

74HC257 

74HC2S9 

74HC273 

74HC299 

74HC36S 

74HC373 

74HC374 

74HC390 

74HC393 

74HC4017 

74HC4020 

74HC4049 

74HC405O 



2.49 

.89 

.95 

1.15 

.99 

1.B9 

1.69 

1.89 

.85 

1.39 

1.89 

4.99 

.99 

2.29 

2.29 

1.39 

1.39 

1.99 

1.39 

.89 



74JHCT: Direct drop- 

and can be intermixed vu 



.69 

69 

69 

69 

79 

BS 

.95 

1.15 

1 16 

2.99 



in replacements lor LS TTL 
ith 74 LS in lite same circuit. 

74HCT166 

74HCT174 

74HCT133 

74HCT194 

74HCT240 

74HCT241 

74HCT244 

74HCT24S 

74HCT257 

74HCT259 

74HCT273 

74HCT367 

74HCT373 

74HCT374 

74HCT393 

74HCT4017 

74HCT4040 

74HCT4050 



3.05 
1.09 
1.39 
1.19 
2.19 
2.19 
2.19 
2.19 
.99 
1.59 
2.09 
1.09 
2.49 
2.49 



O 

o 



III 
O 

< 
92 



Visit our retail store located at 1256 S. Bascom Ave. in San Jose, (408) 947-8881 

nR IX/llOrOrJOV /IPP^ please use your customer number when ordering 

xevaPLn*'! 1 I V 1'lxV^I \J xLJxa^ If |x«^V^xl^ T ERMS Minimum order S 10 06 Ft* shipping and tundl.no inctuoV 52 59 to* UP5 

Ija |* | p. - | /*.* />A riertOft Ground and S3 50 for UPS All Orders ovi-r 1 It) and loretgn olden ntrty n.x»i«. 

lU l\nOWIeS UriVe, LOS UiatOS, OA BbUOU addieonaihipBmgcharo«ph7J»cc™it^louisafcdv1JarinKwtl w llx-.itlxAnlCA 

,li, T»«ll !?_>. on/i coo ennn - /until t>«M~ r-nnn K-«di-nbinusl»relucw..)pp<icatxeiileitai Alinwcnanoii*- rawananhHjlor90d.il> 

".'Yf/K-V' IOII Tree OUU-OOtS-aUUU • (4UO) OOO-bidUU "■»*» othunroe >talM Pnc« aic iilhu-cl lo chanca: without noli,..- wi- ji 

■a fe^, F . v ;.... n-ro nnn-^ _-ri *^4 -*+r* iwpoitsJsle kn lypuq.jpnicn morv Wi- n-urivc Ihe nqhl to hum r«M»lilm and tu 

gjiV l"AA (*HJOj Oi'tS-OHZ/ • leleXl71-1lU sutatltuKoianulaclurvr All niorchandls.. subiocl lo pnot Hk." 

- V^J^V" COPYRIGHT 1987 JDR M1CRODEVICES 

THE JDR M1CRODEVICES LOOO ISA BEOISrEHED TRADEMARK OF JDR MICRODEVICES JDR INSTRUMENTS AND JDR MICRODSYICES ARE TRADEMARKS Ol JUH Mil RODEVlt f. 
IBM IS A TRADEMARK OF INTERNATIONAL BUSINESS MACHINES APPLE IS A TRADEMARK Of APPLE COMPUTER 



CIRCLE 1 13 ON FREE INFORMATION CARD 



EGA CARD AND MONITOR NOW ONLY $569! 



DISK DRIVES 

FOR APPLE COMPUTERS 



CRT MONITORS FOR ALL APPLICATIONS 



AM 50 
$99.95 



FPm 



' V] HT, DIRECT DRIVE 

' 100% APPLE COMPATIBLE 

■ SIX MONTH WARRANTY 



AP-135 
$129.95 





"\ 




n_ 


l^^HS 


H-i 


1 % 



. FULL HT 5HUGART MECHANISM 

• DIRECT REPLACEMENT FOR APPLE 
DESK II 

* SIX MONTH WARRANTY 



■H. 



MAC535 
$249.95 

. 3,5" ADDON DISK DRIVE 

. 100% MACINTOSHCOMPATABLE 

• DOUBLE SIDED BOOK BYTE STORAGE 

- HIGH RELIABILITY DRIVE 

HAS AUTO EJECT MECHANISM 

- FULL ONE YEAR WARRANTY 



«»* 



AD-3C 



rTfff d^ 



T^ZJtf 



. 100% APPLE lie COMPATIBLE. 
READY TO PLUG IN. W SHIELDED 
CABLE S MOLDED is PIN 
CONNECTOR 



■ SIX MONTH WARRANTY 

DISK DRIVE ACCESSORIES 

FDD CONTROLLER CARD £49-95 

lie ADAPTOR CABLE $19.95 

ADAPTS STANDARD APPLE DRIVES 

FOR USE WITH APPLE lie 



KB- 1000 



579.95 



CASE WITH KEYBOARD 
FOR APPLE TYPE MOTHERBOARD 

■ USER DEFINED FUNCTION KEYS 

. NUMERIC KEYPAD W' CURSOR CONTROL 

. CAPS LOCK ■ AUTO-REPEAT 




KEYBDARD-AP 



$49.95 



* REPLACEMENT FORAPPLE II KEYBOARD 
- CAPS LOCK KEV r AUTO-REPEAT 
i- ONE KEY ENTRY OF BASIC OR CP/M 
COMMANDS 



JOYSTICK cB-io $19.95' 

. SET X-Y AXIS FOR AUTO CENTEH OR 

FREE MOVEMENT 
■ FIRE BUTTON FOR USE WITH GAME 

SOFTWARE 
t ATTRACTIVE. SOLID. PLASTIC CASE 
• INCLUDES ADAPTOR CABLE FOR IBM. 

APPLE II, Ik-. II 0, ATARI & VIC 20 61 



POWER STRIP $12.95 

* UL APPROVED 

* 15A CIRCUIT BREAKER 






CASPER 



EGA MONITOR 

EGA & CGA COMPATIBLE 
SCANNING FREQUENCIES: 

15.75 / 21.85 KHz 
RES; 640 a 200 f 3S0 
31mm DOT PITCH. 25 MHe 
16 COLORS OUT OF 61 
14", BLACK MATRIX SCREEN 



CASPER 



RSB MONITOR 

■ COLOR 'GREEN/AMBER 
SWITCH ON REAR 

. DIGITAL RGB-IBM COMPATIBLE 

• 14" NON-GLARE SCREEN 

• RESOLUTION; 640 H x 240V 

■ 39mm DOT PITCH 

■ CABLE FOR IBM PC INCLUDED 



SAMSUNG 
MONOCHROME 

■ fBM COMPATIBLE TTL INPUT 

• 12" NON- GLARE AMBER, 
LOW DISTORTION SCREEN 

• RESOLUTION: 720H N 350V 
i ATTRACTIVE CASE WITH 

SWIVEL BASE 

• ONE YEAR WARRANTY 



FORTROHICS 

MONOCHROME 

- IBM COMPATIBLE TTL INPUT 
t 12" NGN-GLARE SCREEN 
I VERY HIGH RESOLUTION' 
1100 LINES |CENTER| 

■ 25 MHl BANDWIDTH 

' CABLE FOR IBM PC INCLUDED 

IMBEI OS 8IEEH HYWUBLE 



$399.95 $299.95 $119.95 $99.95 

TILT S SWIVEL MONITOR STAND M2" WITH POWER CENTER *39" 



APPLE COMPATIBLE INTERFACE CARDS 





EPROM PROGRAMMER 

- DUPLICATE OH aURN ANY 
27xx SERIES EPROM 

12716 TO 271 2B) 

■ MENU-DRIVEN SOFTWARE 

■ HIGH SPEED WRITE ALGO- 
RITHM 



1GKRIMCIRD 



* FULL 2 YEAR WARRANTY 
■ EXPAND YOUR 48K MACHINE 
TO A FULL 64K OF MEMORY 

» CAfr BE USED IN PLACE OF 
THE APPLE LANGUAGE CARD 



IC TEST GflRD 

- QUICKLY TESTS MANV 

COMMON ECs 
* DISPLAYS PASS OR FAIL 
' TEST 4000 & 74HC SERIES 

CMOS. 7400. 74LS. ML 

74H Si 74S 



RP-525 55995 RAM-CARD S3995 IC-TESTER S129"J 



MOLDED INTERFACE CABLES 

6 FOOT, IKHt SHIELDED. MEETS FCC 



C. ITDH RITEMAN II PRINTER 



>A 



IBM PARALLEL PRINTER CARLE 
CENTRONICS IMALE TO FEMALE) 
CENTRONICS IMALE TO MALE) 
MOOEM CABLE IFOR IBM) 
RS232 SERIAL (MALE TO FEMALE! 
RS232 SERIAL (MALE TO MALE) 
KEYBOARD EXTENDER [COILED! 
1 APPLE II JOYSTICK EXTENDER 



SWITCH BOXES 

ALL LINES SWITCHED, GOLD PLATED 
CONNECTORS. QUAUTY SWITCHES 

2 WAY $39.95 

• CONNECTS 2 PRINTERS TO 1 
COMPUTER OR VICE VERSA 

IB-? (CENTRONICS PARALLEL) 
IB-S ff)S232 SERIAL) 




• 160 CPS DRAFT. 32 CPS NLQ 

. 9 » 9 DOT MATRIX 

- SUPPORTS EPSON 'IBM GRAPHICS 

■ FRICTION AND PIN FEEDS 

> VARIABLE LINE SPACING AND PITCH 

$219.95 

IBM ffiWTER CIBLE $9.95 

I REPLACEMENT HIBBON CARTRIDGE $7.95 j 



NASHUA DISKETTES 

NASHUA DISKETTES WERE JUDGED TO HAVE 

THE HIGHEST POLISH AND RECORDED 

AMPLITUDE OF ANr DISKETTES TESTED 

(COMPARING FLOPff DISKS BTTE B1S4) 



M-MD2D 

M-MD2F 

N-MD2H 

N-FD1 

N-FD2D 



DS/DD SW SOFT 

DS.'QLIAD SW SOFT 

DS/HD SW FOR AT 

SS'DDH"SOFT 

OS/ DO S' SOFT 



S9.90 
$19.95 
$24.95 
SZ7.95 
$34.95 



3 WAY $99.95 

- CONNECTS 3 PRINTERS TO 1 
COMPUTER OR VICE VERSA 

SWITCH -3 P (CENTRONICS PARALLEL) 
SNITCH-3S (RS232 SERIAL) 




BULK DISKETTE SALE 

5V." SOFT SECTOR, DS/DD 
W/TYVEC SLEEVES & HUB RINGS 

$9 9 ° 69C ea 59Cea 

BOX OF 10 HILKQIY5D BULK 01* 250 



DISKETTE FILES 



300B MODEM 



$49.95 



SW DISKFILE 

HOLDS 70 
$9.95 



IV DISKFILE 

HOLDS 40 

$9.95 



FOR APPLE OR IBM 

INCLUDES ASCII PRO-EZ SOFTWARE 
. FCC APPROVEO 

■ BELL SYSTEMS 103 COMPATIBLE 
' INCLUDES AC ADAPTOR 
■AUTODIAL ■ DIRECT CONNECT 



. CABLE FOR APPLE lie 



514.95 I 



SPSeagate 

5W HARD DISK DRIVES 

ST-225 HALF HT 20MB fi5™ &27S 

ST-238 HALF HT 30MB eSn^HLL) S239 
ST-251 HALF HT 40MB 40m* S599 

ST- 277 HALF NT G0MB 40rm ,RLL) CAUL 
ST-4038 F U LL HT 30MB 40rru $553 

.ST-409.fi FULL HT BOMB 2fi.ni Si 195 J 



Vj HEIGHT FLOPPY DISK DRIVES 

5Vt" TEAC PD-S5B DS/OD S109.S5 
5W TEAC FD-55F DS.QUAO ST24.95 
SW'TEAC FD-SSGFVDS.HD S15*.95 
5%" MITSUBISHI DS/HD ST29.95 

3Vi" TOSHIBA KfT DS DO 5149.95 
KIT INCLUDES MOUNTING HARDWARE TO 
FIT 5W S, FACEPLATES FOR AT I XT 

DISK DRIVE ACCESSORIES 

TEAC SPECIFICATION MANUAL S5.M 

TEAC MAINTENANCE MANUAL £25 0-D 
W HT MNTG HARDWARE FOR IBM 32.95 
MO UN Tl NG fl Al LS FOR ISM AT $4 95 

"V" POWER CABLE FOR SW FODs 52.95 
SW FDD POWER CONNECTORS M.tS J 



DISK DRIVE ENCLOSURES 
WITH POWER SUPPLIES 

C*B-iSV5 DUAL SLIMLINE BV«" «49»> 
CHB-1FH5 FULL HT 5V," '69 1! 

CHB-2SVB DUAL SLIMLINE 8" '209" 
CaB-JFHB DUAL FULL HT 6" '218" 




[BUILD STEVE CIARCIA'S 

INTELLIGENT 

EPROM PROGRAMMER 

AS SEEN IN BYTE, OCT. M 

• STAND-ALONE OR RS-232 SERIAL 
OPERATION 

■ MENU SELECTABLE EPROM TYPES- 
NO CONFIGURATION JUMPERS 

• PROGRAMS ALL 5 V 27XXX EPROMS 
FROM 2716 TO 27512 

- READ. COPY OR VERIFY EPROM 

. UPLOAD /DOWNLOAD INTEL HEX FILES 

• PROGRAMMER DRIVER USER 
MODIFIABLE 

0NLY$199 

KIT INCLUDES PCB AND ALL 

COMPONENTS EXCEPT CASE & 

POWER SUPPLY 



CALL FOR VOLUME QUOTES copyright 1987 jdr micro-devices 



CIRCLE 182 ON FREE INFORMATION CARD 



I 



94 



QUALITY IBM COMPATIBLE MOTHERBOARDS 

FROM MODULAR CIRCUIT TECHNOLOGY 

I TURBO 4.77 / 8 MHZ $129.95 

JDR PART #: MCT-TURBO 



* 4.T7 OR S MHjs OPERATION WITH 80BB-2 
& OPTIONAL B0S72 CO PROCESSOR 

* DYNAMICALLY ADJUSTS SPEEO DURING 
DISKETTE OPERATION FOR MAXIMUM 
THROUGHPUT AND RELIABILITY 

* CHOICE OF NORMAL / TURBO MODE OR 
SOFTWARE SELECT PROCESSOR SPEED 

| STANDARD 477 MHZ $109.95 

JDR PART #: MGT-XTMB 

* HOB B CPU. OPTIONAL &0B7 CO-PROCESSOR 

* 3 EXPANSION SLOTS 

i EXPANDABLE TO 540K ON BOARD 

Mi.HOBV /OK RAM INSTALLED) 
i A LL I Ct SOC K ETE D -HI G H EST QU ALI T¥ PC B 

* ACCEPTS 2764 OR 27t2H ROMS 

BOTH WITH FREE MCT BIOS! 



FARADAY 
FDD CONTROLLER 

JDR PART »: FAR-FDD 

■ SUPPORTS UP T0 1 INTEHNALLY 
MOUNTED FDO> 

■ IBM COMPATIBLE. INTERFACES TO 
360K OR 72DK USING DOS 3.20 

< INCLUDES CABLE FOR 2 DISK DRIVES 




IBM COMPATIBLE 
FLOPPY DISK DRIVE 

JDRPARTIlFDD-XO 

GOOD QUALITY DRIVES 

BY MAJOR MA NUFAC TURERS SUCH AS 

QUME, TANDON i CDC 

* 5W r HALF HEIGHT * DS/DD 

■ 360K STORAGE CAPACITY * 48 TPI 



$24.95 $69.95 



IBM STYLE 
COMPUTER CASE 

AN ATTRACTIVE STEEL CASE WITH 

A HINGED LID. FITS THE POPULAR PC/XT 

COMPA TIBLE MOTHERBOARDS 



BUILD YOUR OWN 256K 
XT COMPATIBLE SYSTEM 



■.1li,i']|.Hil'llM,l'1 




■ SWITCH CUT-OUT ON SIDE FOR PC/XT 
STYLE POWER SUPPLY 

■ CUTOUT FOR 3 EXPANSION SCOTS 

■ ALL HARDWARE INCLUDED 

$34.95 

SLIDE TYPE CASE $39.95 



SIO995 

PRO-BIOS (A $20 VALUE) FREE! 

256K RAM $26" 

130 WATT POWER SUPPLY *69" 

FLIP-TOP CASE '34" 

KEY TRONIC "KEYBOARD '49" 

360K DRIVE $69" 

FARADAY CONTROLLER $24" 

MONOCHROME ADAPTOR '49" 

FORTROKICS MONITOR '90" 



TOTAL: 



$536.15 



IBM COMPATIBLE KEYBOARDS 

MCT-5150 



$59.95 



■ "5150" STYLE KEYBOARD 
. FULLY IBM COMPATIBLE 

• LED STATUS INDICATORS FOH CAPS & 
NUMBER LOCK 

• LARGE. EASY TO REACH SHIFT & 
RETURN KEYS 

. S3 KEY TYPEWRITER LAYOUT 



OLi 



i_|_J_U H 



MCT-5151 



$79.95 



i~t~t ; i''-'- Y-firr-n 



. REPLACEMENT FOR KEY THONIC'- 
KB-5151 KEYBOARD 

• SEPARATE CURSOR B, NUMERIC KEYPAD 

• CAPS LOCK & NUMBER LOCK 
INDICATORS 

. IMPROVED KEVBOARD LAYOUT 



MCT-5969 



$59.95 



^ 



^TTT*! 



> IBM AT STYLE LAYOUT 
• SOFTWARE AUTOS ENSE FOH XT OR AT 
COMPATIBLES 

■ EXTRA LARGE SHIFT & RETURN KEYS 

■ LED INDICATORS FOR SCROLL, CAPS ft 
NUMBER LOCK 

r AUTO REPEAT FEATURE 




MCT-5339 



$99.95 



> IBM ENHANCED STYLE LAYOUT 

1 SOFTWARE AUTO SENSE FOR XT OR AT 

COMPATIBLES 
1 12 FUNCTION KEVS 

■ EXTRA LARGE SHIFT & RETURN KEYS 

• LED INDICATORS FOR SCROLL. CAPS & 

NUMBER LOCK 
i AUTO HEP EAT FEATURE 

■ SEPARATE CURSOR PAD 



EASYDATA MODEMS 



All models feature auto-diali answer I radial on busy, Hayes compatible, power up self 
test, toucbtone or pulse dialing, built-in speaker, PC Talk III Communications 
software. Bell Systems 103 & 2I2A full or half duplex and more. 

INTERNAL 
EASYDATA-12H $99.95 

1200 BAUD HALF CARD 

EASYDATA-12B $119.95 

1200 BAUD 10" CARD 

EASYDATA-24B $199.95 

2400 BAUD FULL CARD 

EXTERNAL 

NO SOFTWARE INCLUDED 

EASYDATA- 1 2D $119.95 

1200 BAUD 

EASYDATA-24D $219.95 

2400 BAUD 




vxf" 



ill 



U*. 



DISPLAY CARDS 

FROM MODULAR CIRCUIT TECHNOLOGY 



MCT-EGA 



$179.95 



KXM IBM COMPATIBLE, PASSES IBM EGA DIAGNOSTICS 

• COMPATIBLE WITH IBM EGA. COLOR GRAPHICS 
AND MONOCHROME ADAPTORS 

■ TRIPLE SCANNING FREQUENCY FOR DISPLAY 
ON EGA. STANDARD RGB DR HIGH RES- 
OLUTION MONOCHROME MONITOR 

• FULL 25SK OF VIOEO RAM ALLOWS 640 I 350 
PIXELS IN 1 6 OF 64 COLORS 

• LIGHT PEN INTERFACE 




MCT-CG 



$49.95 



COMPATIBLE WITH IBM COLOR GRAPHICS STANDARD 

* SHORT SLOT CARD USES VLSI CHIPS TO 
INSURE RELIABILITY 

t SUPPOHT5 RGB, COMPOSITE MONOCHROME 

& COLOR AND AN Rf MODULATOR OUTPUT 
fc 320 x 200 COLOR GRAPHICS MODE 

* 640 a 200 MONO GRAPHICS MODE 
'LIGHT PEN INTERFACE 



MCT-MGP 




affiCv 



$59.95 



COMPA TIBLE WITH IBM MONOCHROME AND HERCULES GRAPHICS STANDARDS 
« SHORT SLOT CARD USES VLSI CHIPS TO 

INSURE RELIABILITY 
i PARALLEL PR! NTE R PORT, CONFIGURABLE AS 

LPT1 OR LPT2 

• 720 x 348 GRAPHICS MODE 

• LOTUS COMPATIBLE 

• CAN HUN WITH COLOR GRAPHICS CARD IN 
THE SAME SYSTEM 



MCT-MG 





$79.95 



COMPATIBLE WITH IBM MONOCHROME AND HERCULES GRAPHICS STANDARDS 

• SERIAL PORT OPTION 

• PARALLEL PRINTER PORT 
. 720 it 348 GRAPHICS MODE 

• 80 x 25 TEXT MODE 

■ LOTUS COMPATIBLE 

■ SELECTABLE TO RUN ALONG WITH COLOR 
GRAPHICS CARD IN THE SAME SYSTEM 

MG-SERIftL OPTIONAL SERIAL PORT 'IS 19 




MCT-MONO 



$49.95 



ANOTHER FANTASTIC VALUE FROM JDR! 
IBM COMPATIBLE TTL INPUT • 720 * 34S PIXEL DISPLAY 

PLEASE NOTE THIS CARD WILL NOT RUN LOTUS GRAPHICS 
AND DOES NOT INCLUDE A PARALLEL PORT 



EPROM PROGRAMMERS 

FROM MODULAR CIRCUIT TECHNOLOGY 



MCT-EPROM 



$129.95 



PROGRAMS 27xx AND ZTxrx SERIES EPROMS UP TO 27512 



• SUPPROTS VARIOUS MANUFACTURERS 
FORMATS WITH 12.5, 21 AND 25 VOLT 
PROG RAMM IMG 

• MENU-DRIVEN SOFTWARE ALLOWS 
EASY MANIPULATION OF DATA FILES 

• SPLIT OR COMBINE THE CONTENTS OF 
SEVERAL EPROMS OF DIFFERENT SIZES 

• READ, WRITE, COPY. ERASE CHECK AND 
VERIFY WITH EASY ONE KEY SELECTION 

• INCLUDES SOFTWARE FOH STANDARD 
HEX AND INTEL HEX FORMATS 

4 GAMG PROGRAMMER M 89" 
10 GANG PROGRAMMER *299« 




MCT PRODUCTS CARRY A ONE YEAR WARRANTY copyright i987 jdr micro-devices 



CIRCLE 183 ON FREE INFORMATION CARD 



1200B MODEM $9995 K& 2400b modem S19995 



MULTIFUNCTION CARDS 

FROM MODULAR CIRCUIT TECHNOLOGY 



MCT-MF 



$79.95 



ALL THE FEATURES OFASTS SIX PACK PLUS AT HALF THE PRICE! 
OMSK DYNAMIC RAM USING 416A. 
INCLUDES SERIAL PORT. PARALLEL PRINTER 
PORT. GAME CONTROLLER PORT AND 
CLOCK /CALEN DA H 

SOFTWARE FOR A RAMD1SK. PRINT SPOOLER 
AND CLOCK-CALENDAR 



MCT-ATMF 



$139.95 



ADDS UP TO 3 MB OFT BIT RAM TO THE A T 



USER EXPANDABLE TO 1 .5 MB OF ON-ROARD 

MEMORY <NO MEMORY INSTALLED! 

FLEX ISLE ADDRESS CONFIGURATION 

INCLUDES SERIAL PORT. PARALLEL PORT AND 

CLOCK/CALENDAR 

OPTIONAL PIGGYBACK BOARD PERMITS 

EXPANSION TO 3 MH 

»TMF-SErI»L 2nd serial port '24" 
MCT-ATMF-MC '29" 

PIGGYBACK BOARD (ZEHQ K INSTALLED) 



MCT-MIO 



$79.95 



A PERFECT COMPANION FOR OUR MOTHERBOARD 



* 2 DHIVE FLOPPY DISK CONTROLLER 

I N C LU E S S E HI A L PO RT. PA R ALLE L PORT. 
GAME PORT AND CLOCK/CALENDAH 
WITH HATTERY BACK-UP 

SOFTWARE FOH A RAMOISK, PRINT SPOOLER 
AND CLOCK/CALENDAR 

MIO-SFJIll 2nd SERIAL PORT *15" 



MCT-10 



$59.95 



USE WITH MCT-FH FOR A MINIMUM OF SLOTS USED 



SERIAL PORT ADDRESSABLE ASCOMl. COM2, 

COM3 OR COM4 

PARALLEL PRINTER PORT ADDRESSABLE AS 

LPT1 OT LPT2 (n378 OR «278) 

CLOCK /CALENDAR WITH A 

BATTERY BACKUP 



ID-SERIAL 



2nd SERIAL PORT 



'15« 



MCT-ATIO 



$59.95 



USE WITH MCT-A TFH FOR A MINIMUM OF SLOTS USED 

• SERIAL PORT ADDRESSABLE AS COM1. COM2, 

COM3 OR COM4 
» PARALLEL PHINTEH PORT ADDRESSAHLE AS 

LPTA OR LPTB [«378 OR »278| 
■ GAME PORT 
- USES 18450 SERIAL SUPPORT CHIPS FOR HIGH 

SPEED OPERATION IN AN AT 

UTIO-JEIIIL 2nd SERIAL PORT '2A" 



Vol 



RAM CARDS 

FROM MODULAR CIRCUIT TECHNOLOGY 



MCT-RAM 



$69.95 



,4 CONTIGUOUS MEMORY SOLUTION FOR YOUR SHORT OR REGULAR SLOT 

SHORT SLOT, LOW POWER PC COMPATIBLE 

DESIGN 

CAN OFFER UP TO 576K OF ADDITIONAL 

MEMORY 

USER SELECTABLE CONFIG UR ATtON 

AMOUNTS OF 1 92 r 384. 512. 2S6 & B7GK. 

USING COMBINATIONS OF 64 & 25GK BAM 



TO 



MCT-ATRAM 



$149.95 



A POWER USER'S DREAM, 4MB OF MEMORY FOR THE A T 

USER EXPANDABLE TO 2MB OF ON BOARD 

MEMORY 

USES FULL 16 BIT PARITY CHECKED MEMORY. I 

64K OR 256K DYNAMIC RAM 

FLEXIBLE STARTING ADDRESS, HOUND OUT 

CONVENTIONAL MEMORY TO 640K & ADO 

EXTENDED MEMORY ABOVE 1MB 

MCT-ftTMM-MC *3B« 

2MB PIGG TRACK BOARD (ZERO K INSTALLED) 



MCT-EMS 



$129.95 



2MB OF LOTUS/tNTEL/MICROSOFT COMPATIBLE MEMORY FOR THE XT 

CONFORMS TO LOTUS/INTEL EMS 
USER EXPANDABLE TO 2 MB 
USES 54K OB 256K DYNAMIC RAM 

(NO MEMORY INSTALLED) 

USE AS EXPANDED OR CONVENTIONAL 

MEMORY. RAMDtSK OR SPOOLER 

SOFTWARE INCLUDES EMS DEVICE DRIVERS. J 

PHINT SPOOLER AND RAMDtSK 



<5P Seagate 

HARD DISK SYSTEMS 

20 MB 30 MB 
$339 $399 

Systems include half height hard disk drive, hard disk drive controller, 
cables and instructions. Drives are pro-tested and warranted for one year. 



\88seagate40 mb at drive 



m\ 



■ 111 



ifettKl 



WtfM 



FAST 40ms ACCESS TIME 

$599 



DISK CONTROLLER CARDS 

FROM MODULAR CIRCUIT TECHNOLOGY 



MCT-FDC 



$34.95 



QUALITY DESIGN OFFERS 4 FLOPPY CONTROL IN A SINGLE SLOT 



• INTERFACES UP TO 4 FODs TO AN IBM 
PC OR COMPATIBLE 

• INCLUDES CABLING FOR 2 INTERNAL 
DRIVES 

' USES STANDARD DB37 CONNECTOR 

FOR EXTERNAL DRIVES 
. SUPPORTS BOTH DS/DD AND OS/OD 

WHEN U5EOW' DOS 3.2 OR JFORMAT 



SLOT,, 



MCT-HDC 



$89.95 



MCT-ftTEMS at version of the mct-ems $139 95 



HARD DISK CONTROL FOR WHA T OTHERS CHARGE FOR FLOPPY CONTROL 

I IBM XT COMPATIBLE CONTROLLER 

SUPPORTS 16 DRIVE SIZES INCLUDING 

S, 10, 20. 30 & 40MB 
. OPTIONS INCLUDE THE ABILITY TO 

DIVIDE 1 LARGE DRIVE INTO 2 

SMALLER. LOGICAL DRIVES 
• INCLUDES CABLING FOR 1 INTERNAL 
DRIVE 



MCT-RLL 



$119.95 



GET UP TO 60% MORE STORAGE SPACE ON YOUR HARD DISK 

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. USE WITH ST 238 DRIVE TO ACHIEVE 
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MCT-FH 



$139.95 



STARVED FOR SLOTS? SA TISFY IT WITH THIS TIMEL V DESIGN 
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■ FLOPPY INTERFACE SUPPORTS BOTH 
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• ALL POPULAR HDD SIZES ARE 
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40MB 

■ CAN DIVIDE 1 LARGE DRIVE INTO 2 
SMALLER, LOGICAL OH IVES 



MCT-ATFH 



$169.95 



FLOPPY AND HARD DISK CONTROL IN A TRUE AT DESIGN 

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• 16 BIT BUSS PROVIDES RAPID DATA 
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■ FULLY SUPPORTED BY AT HIOS 



* < illD ■\/ll#>r > SWl Al I IS^AO 1 10 Knowles Drive, Los Gatos, CA 95030 

* *JL-/lt I V 111*1 UUCVItrCO Toll Free 800-538-5000 • (406) 866-6200 • FAX (408) 378-8927 • Telex 171-110 

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| Cartain at'ly PCs may not run *t a MHx-tn*M macfim f»r b* switched 10 on* of eta ilww •p*wk 

6 66 MHi t«% 7,37 MH^5G\ 6.0 MMi=87% 



PAGE WIRE WRAP WIRE 

PRECUT ASSORTMENT 

IN ASSORTED COLORS 327.50 

lOOna: 5 5", 6.0'. 6.5", 7.0" 
250en: 2.5". 4.5". 5.0" 
500>a: 3.0", 3.5". 4,0" 



WIRE WRAP PROTOTYPE CARDS 

FR-4 EPOXY GLASS LAMINATE 
WITH GOLD-PLATED EDGE-CARD FINGERS 



SPOOLS 



100 feat »4.30 
500 (Bat 513,25 



250 fael $7,25 
1000 feet S21 .95 



Please specify color: 

Blue, Black. Yellow or Red 



EXTENDER CARDS 




IBM-PC 
IBM-AT 



$29.95 
S39.95 



SPECIAL ENDS 7/31/87 




SOCKET-WRAP I.D.™ 

• SLIPS OVER WIRE WRAP PINS 

■ IDENTIFIES PIN NUMBERS ON WRAP 
SIDE OF SO Ann 

• CAN WRITE ON PLASTIC: SUCH AS IC II 
PINS PART;: PCK. OF PRICE 

S IDWRAP OS 10 1.95 

14 IDWRAP14 10 1.55 

15 IDWRAP 16 10 1.9S 
18 IDWRAP 18 5 1.95 
20 IDWRAP 20 5 1.95 

22 IDWRAP 22 5 1.95 
24 IDWRAP24 5 1-95 

23 IDWRAP 28 5 1.95 
40 IDWRAP 40 5 1.95 

PLEASE ORDER BY NUMBER OF 
PACKAGES 1PCK. OF) 



FRAME STYLE 
TRANSFORMERS 



12.6VACCT 

12.6VACCT 

12.6VACCT 

1 25.2V AC CT 



2 AMP 
4 AMP 
B AMP 
2 AMP 



5.95 
7.95 
10.95 
7.95 . 



r 25PIND-SUB 

BENDER 

CNAHQERS 

$7.95 





CAPACITORS 








TANTALUM 






I.Offf 


15V 


.35 


.47** 


35V 


.45 


G.8 


15V 


.70 


1.0 


35V 


.45 


10 


15V 


,B0 


2.2 


35V 


.55 


22 


15V 


1.35 


4.7 


35V 


.65 


.22 


35V 


.40 


10 


35V 


1,00 






DISC 






10pl 


50V 


.05 


650 


SOV 


.05 


22 


50V 


.05 


-OOljrf 


50V 


.05 


27 


50V 


.05 


.0022 


SOV 


.05 


33 


50V 


.05 


.005 


SOV 


.05 


47 


SOV 


.05 


.01 


SOV 


.07 


59 


SOV 


.05 


.02 


50V 


.07 


100 


SOV 


.05 


.05 


SOV 


.07 


220 


50V 


.05 


.1 


12V 


.10 


550 


SOV 


.05 


.1 


50V 


.12 




MONOLITHIC 






.01 it 


50V 


.14 


-V 


50V 


.18 


.047*4 


50V 


.15 


■*7jrf 


50V 


.25 




ELECTROLYTIC 






RADIAL 




AXIAL 




Iff 


2SV 


.14 


V* 


50V 


.14 


2.2 


35V 


.15 


10 


50V 


.16 


4.7 


50V 


.IE 


22 


16V 


.14 


10 


50V 


.IB 


47 


SOV 


20 


47 


35V 


.IS 


100 


35V 


.25 


100 


15V 


.18 


220 


25V 


30 


220 


35V 


.20 


470 


50V 


.50 


470 


25V 


.30 


1000 


16V 


.60 


2200 


16V 


.70 


2200 


16V 


.70 


I 4700 


25V 


1.45 


4700 


16V 


1.2b 



DATARASE EPROM ERASER $34.95 

• ERASES 2 IN 10 MINUTES _. __^__ 

■ COMPACT-NO DRAWER __■ 

- THIN METAL SHUTTER 

PREVENTS UV LIGHT 

FROM ESCAPING ■ 



1/4 WATT RESISTORS 

5% CARBON FILM ALL STANDARD VALUES 
FROM 1 OHM TO 10 MEG OHM 

10 PCS ssrwvBkM .05 100 PCS same value .02 

[ 50 PCS iamevakHt .025 1000 PCS same vahjc .015 , 





RESISTOR NETWORKS 




SIP 


10 PIN 


9 RESISTOR 


.69 


J SIP 


8 PIN 


7 RESISTOR 


.59 


: DIP 


16 PIN 


8 RESISTOR 


1.09 


DIP 


16 PIN 


"IS RESISTOR 


1.09 


1 DIP 


14 PIN 


7 RESISTOR 


.99 


1 DIP 


14 PIN 


13 RESISTOR 


.99 



SPECIALS OH BYPASS CAPACITORS 

.01 fit CERAMIC DISC 100/S5-00 

.01 (if MONOLITHIC 100/S10.00 

.1 ^f CERAMIC DISC 100/S6.50 

.1 (A MONOLITHIC 100/S12.50, 





WIS 


H SOLDERL 


ESSBI 


IEADB0J 


RDS 






PART 
NUMBER 


DIMENSIONS 


DISTRIBUTION 
STRIHSI 


TIE 
POINTS 


TERMINAL 
STRIP(SI 


TIE 
POINTS 


BINDING 
POSTS 


PRICE 


WBUD 


.38 jc 6.50" 


1 


100 






™ 


2.9S 


WBU-T 


1.38 > 6.50" 






1 


630 




6-95 


WBU204-3 


3.94 x 8.45" 


1 


100 


2 


1260 


2 


17.95 


WBU-204 


5,13*3.45" 


4 


400 


Z 


1260 


3 


24.95 


WBU20J ! 


6.38 x 9.05" 


5 


500 


3 


1890 


4 


29.95 


WBLJ-208 


8 25 x 9.45" 


7 


700 


4 


2520 


4 


39,95 



IBM-PR2 .___ 

IBM 

BOTH CARDS HAVE SILK SCREENED LEGENDS 

AND INCLUDES MOUNTING BRACKET 

IBM-PR1 WITH -5V AND GROUND PLANE , , , 427.95 

IBM-PR2 AS ABOVE WITH DECODING LAYOUT $29.95 

S-100 

P100-1 BARE -NO FOIL PADS a 115.15 

P100-2 HORIZONTAL BUS ,■ , . ■ *.,.;..,,-,., »21 SO 

PI 00 3 VERTICAL BUS ............ . *Z1 SO 

PlOO-4 SINGLE FOIL PADS PEH HOLE 422.75 

APPLE 

P5001 BARE . NO FOIL PADS £15.15 

P500-3 HORIZONTAL BUS $22.75 

P500 4 SINGLE FOIL PADS PER HOLE 421.30 

L 7060-45 FOR APPLE Ha AUX SLOT S30.00 



PS-IBM 



SWITCHIHQ POWER SUPPLIES 



• FOR IBM PC-XT COMPATIBLE 

• 135 WATTS 

• :i V @ 1 5A r ■ I ZV @ 4.ZA 

-5V(£ ,SAh -12V(S .5A 

• ONE YEAR WARRANTY 

PS-IBM/ 150 

| PS-IBM-150 $79.95 

• FOR IBM PC XT COMPATIBLE 

■ 150 WATTS 

* -12V @ 5.2A. .5V (S 18A 
.12V @ .5A, -5V (K 5A 

■ ONE YEAR WAHRAIMTY 



PS- 130 



$99.95 



' 130 WATTS 
I SWITCH ON HE AH 
• FOR USE IN OTHER IBM 
TYPE MACHINES 

■ 90DAYWAHRANTY 

PSA $49.95 

■ USE TO POWER APPLE TYPE 
SYSTEMS. 7S.5 WATTS 

*+SV@7A, »12V(S3A 
-5V m .5 A. -12V g .5 A 
' APPLE POWEH CONNECTOR 




i PS- 1558 



$34.95 




. 75 WATTS. UL APPROVED 
■ -SV@7A, -12V (J) 3A 
-12V@>Z50ma. -5V@ .lOiVi.i 

BOOKSby STEVE CI 

B1ULD YOUR OWN 
Z80 COMPUTER $19.95 

CIRCUIT CELLAR VOL 1 517.95 

CIRCUIT CELLAR VOL 2 318.95 

CIRCUIT CELLAR VOL 3 S1S-95 

CIRCUIT CELLAR VOL 4 $18.95 

. CIRCUIT CELLAR VOL 5 S19.9S 



LITHIUM BATTERY 

AS USED IN CLOCK CIRCUITS 



3 VOLT BATTERY $3.95 

, BATTERY HOLDER S1.49 




MUFFIN FANS 

SO 14.95 3-03" SO 
3.18" SQUARE 16,35 

6 LINE CORDS 

dueler .33 3 conrfucti 

ductar w female socket 

EMI FILTER $4.95 



| 3 15' SO- 14.95 3-53" SO 14.95 

3.15" SQUARE 16.35 



| 2 conductor .33 3 conductor -99 

3 conductor w fomelc sockat 1,49 



2 VOLUME SET 

IC MASTER 

THE INDUSTRY STANDARD 

$129.95 



ol 



96 



Visit our retail store located at 1256 S. Bascom Ave. in San Jose, (408) 947-8881 

|| \^y I\ /ll*~*6*/^/~^Ck\ fMlT*QB PLEASE USE YOUR CUSTOMER NUMBER WM 

•JLvIl I V lll^rl vJtJIjrV I V*trO IERMS Mmimum SIC 00 Foi pping and handling im 

. _^ , ai Ar/^A Ground and S3.50 tor UPS An. Orders over 1 lb. and foreign 

110 KnOWleS DriVe, LOS GatOS, CA 95030 .rdditailfllihippingrhargriS -pleaseeonlactoursalesdepartmen 

aai i-*r* #«M«#fc restdenls musl include applicable sales tan Allrnerchandiseisw 

Toll Free 800-538-5000 • (408) 866-6200 «*« o»w«i*i :sui«i puck an.- subtuci io change wimoui 

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FAX (408) 378-8927 • TeleX 171-110 substitute manulaclurei All rrKrchandLse subject So pool sale- 



y^^ COPYRIGHT 1987 JDR MICRODEVICES 

THE JDR MICRODEVICES LOGO IS A REGISTERED TRADEMARK OF JDR MICRODEVICES. JDR INSTRUMENTS AND JDR MICRODEVICES ARE TRADEMARKS OF JDR MICRODEVICES 
IBM IS A TRADEMARK OF INTERNATIONAL BUSINESS MACHINES APPLE IS A TRADEMARK OF APPLE COMPUTER 



CIRCLE 185 ON FREE INFORMATION CARD 



Radio /hack Part/ Place 



THE BUILDER'S STORE! OVER 1000 COMPONENTS IN STOCK 



Communications 
Circuit Book 



«|49 

A Must 

For Project 

Builders 

The latest of 
the "hands- 
on" electronic- 
project books by Forrest M, Mims 
in. Includes projects (or wired and 
wireless voice and code systems, 
shortwave listening and much 
more. Contains 48 pages with 
schematics. #276-5015 




Unusual Buzzers 




(5) Trl-Sound Alarm. Contains an 
IC. driver circuit and 8-ohm 
speaker. Three distinctive sounds. 
3 VOC. #273-072 5.95 

(6) Electronic Chime. Melody- 
synthesizing EC and speaker 
combo produce a pleasant "ding- 
dong" sound. Operates 6 to 18 
VDC. #273-071 7.95 



Deluxe Enclosures 




Vented steal tops, easy-to-work 

aluminum chasis. With protective 
rubber feet and hardware. 



S.ze 


Cat. No 


Each 


3V.x2Vex4" 
4x2%x 6" 
5V« x 3 x 5W 


270-251 
270-252 

??n.?53 


2.99 
3.99 
4.99 



Archer^ Hand Tools 




Professional Quality 



(13) 5V«* Long Nose Pliers. 
Spring return, insulated grips. 
#64-1812 5.99 

(14) 4'/2" Diagonal Cutters. 
Spring return, long lasting and in- 
sulated grips. #64-1813 5.99 

(15) 6" Locking Forceps. Use as 
a temporary heal sink and to pick 
up or hold parts. #64-1866 . 4.95 



Attention-Getting LEOs 




(1) Super-Bright Red. Outputs 
300 mcd, 20 mA #276-066, 1.19 

(2) Blinking Red. MOS driver and 
red LED combo. #276-036 . . 1.29 

(3) Blinking Green. 

#276-030 1.29 

(4) CdS Photocell. Mated 200 



mW, 170 volts. #276-116. 



1.79 



Panel Switch Values 



(7) Lighted SPST Normally Open 
or Normally Closed. Rated 5 
amps at 250 VAC. 12-volt lamp. 
#275-676 S.95 

(8) SPST Rocker Switch. Rated 6 
amps, 125 VAC #275-690 . . 1.89 
DPDT. #275-691 2.49 

(9) SPDT Mini-Toggle. Rated 5 
amps. 125 VAC. #275-603 . . 1.49 



Miniature PC Pots 




Rated at Vs-watl. Sealed against 
noise-causing contaminants. 



Ohms 


Cat. No. 


1k 

10k 

25 k 

100k 


271-333 
271-335 
271-336 
271-338 



Archer coax Cable 




Low As 



per foot 



Low loss— no more than 4.0 dB per 
100 feet at 50 MHz. 


RG 

Type 


Ohms 


Vel 

Fact. 


Cat. 

No. 


Price 
Per Ft. 


8' 

8 
58 
59 


52 
52 
52 
75 


66% 
75% 
66% 

75% 


278-1323 
278-1328 
278-1326 
278-1327 


.36 

.21 
.16 
.16 



•NEW! 95% Shielding. 



Hotline" 



Save With our 
Order Service 

We send your order 
directly to the 
Radio Shack near you. 
We pay the postage. 
Delivery time on most 
items is one week. 



Your Radio Shack store 
manager can special-order 
a variety ot parts and ac- 
cessories not listed in our 
catalog— tubes, linear and 
digital iCs, diodes, transis- ' / 

tors, crystals, phono cartridges and more. There's no 
minimum order requirement for this convenient ser- 
vicel Your order will be sent to your nearby Radio 
Shack store, and we'll notify you when it arrives. 




%> 



Put These High-Tech ics to work 



(10) 




<11> 



WW 



With Data, Circuit Sampt 

(10) SP0256-AL2 Speech Synthesizer. MOS/LSI device with built-in pro- 
gram easily interfaces with most computers. Requires 3.12 MHz crystal 
(special order via ■'hotline" above). 28-pin DIP. #276-1784 12.95 

(11) CTS256-AL2 Text-to-Speech tC. Preprogrammed 8-bil processor 
translates ASCII into control data for figure 10. Requires 10 MHz crystal 
[special order). 40-pin DIP. #276-1786 16.95 

(12) SSI 202 Touch-Tone Decoder IC. Easy-to-use OTMF receiver is just 
right for remote-control applications. Requires a minimum of support parts 
and is easily interfaced with most microprocessors. #276-1303 .... 12.95 



Tantalum Caps 



Maximum Capacity 
In an Extremely 
Small Package 



Low As 

49* 

Each 



IC pin spacing 


. 20% tolerance. 


F 


WVDC 


Cat. No. 


Each 


0.1 

0.47 

1.0 


35 
35 
35 


272-1432 
272-1433 
272-1434 


.49 
.49 
.49 


22 
10 
22 


35 
16 
16 


272-1435 
272-1436 
272-1437 


.59 
.69 
.99 



28-RangeFETVOM 




Top-Quality Memory 




Upgrade 
Your Computer 

4164 64K Dynamic RAM. 150 ns 
access time, low-power design 
(230 mW, typical). Single 5 VDC 

supply. #276-2506 3.95 

TMS 4256 256K Dynamic RAM. 
150 ns maximum access, low- 
power 16-pin DIP with specs and 
pin-out. Single 5 VDC supply. 
#276-1252 6.95 



Dual-Tracking DC Supply 



Big 5" 
Color- 
Coded 
Scale 



Works like a solid-state VTVM! 
Super-sensitive — 10-megohm input 
impedance. With 28 ranges and 
"beep" continuity. Includes test 
leads and spare fuse. Requires one 
9V and one "C" battery. #22-220 




Delivers stable DC with extremely 
tow ripple at precisely the voltage 
you need. Adjustable from to 15 
VDC. or series output provides up 
to 30 VDC. Selectable independent 
or slave operation of two voltages. 
Meter for monitoring voltage or cur- 
rent of either output. UL listed. 
#22-121 69.95 



Over 1000 items in stock: Binding posts, Books, Breadboards, Buzzers, Capacitors, 
Chokes, Ciips, Connectors, Fuses, Hardware, ICs, Jacks, Knobs, Lamps, Memory 
Chips, Multitesters, PC Boards, Plugs, Power Supplies, Rectifiers, Relays, Resis- 
tors, Switches, Tools, Transformers, Transistors, Wire, Zener Diodes, more! 



Radio /hack 

A DIVISION OF TANDY CORPORATION 
Prices apply at parmeipating Radio Sriack stores and oaicrs 



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> 

C 

a 

c 

CO 



CO 
-J 



97 




illMIU'lJl^- fJilMlllUilJilSl 



ALL ELECTROMCS CORP. 

(ml m^mmm mm 



SPRING LEVER 
TERMINALS 



is 



Two color 
codtd 

twminats on a 
alurdy 244" x 
3 ' < bakelita 
piste 

Gnat tor speaker cndoiurcs or 
power supplies. 
75* EACH 10 Jot $6.00 



FUSES Q^^J 



3AG (AGO SJZE 

], 1^.2.2^.3.4. 5, SAMP 

1.2.3,4. SAMP 1**^=*» 
5 of j ny ON E am perage 7 $ -: 



^PHOTO-FLASH 
CAPACITORS 

^170 MFD 330 Volt 

CAT! FPC-170 

"7 5c each 

400 MFD 330 Volt 
CAT) PPC-4 00 $1.00 ea 



LIGHT ACTIVATED 
MOTION SENSOR 

This device 
contains a 
photocell 

which scuS'.-i 
sudden changes 
in ambient liqht . 
When an object or person 
passes., within it's field 
of view (about b") it beeps 
for several seconds then resets 
Could be used as a door annun- 
ciator or modified to trigger 
other devices. 5 1/2" x 4" x J . 
Operates on 6 Vdc Requires 4 t\h 
batteries (not included)* 
CATi LSMU S5.75 pet unit 




SOUND EFFECTS BOARD 

PC board with 2 1/4" speaker, 
2 LEDsh IC h battery snap, 
other components 2 3/8 p x 3". 
When switch is pushed 
board beeps and Leds lightl r. 
Operates on 9v battery 
(not included) 
Experimenter ' s delight' 
CAT* ST- 3 SI. 2 5 ea. 




4 inch 
paper 



COMMODORE PRINTER PLOTTER 

Commodate ModM * 1520 

Feu* cok* X-Y plotter, standard VIC 
sana! in I. efface allows easy connection 
10 Commodorg 64 compuEnrg. Up TO 80 
ch&raciera. par iwe. 

CAT I CONM520 

$49.95 each 
EXTRA pen seta $1.50 per set. 




MINIATURE TOGGLE SWITCHES 

ALL ARE HATED 5 AMPS® 125 VAC 



COMPUTER GRADE 
CAPACITORS 
1,*V00 mfd, 200 Vdc 

3" X 2" dia. 52.00 

6,400 irrfd 60 Vdc 

4 1/4"* 1 3/8" dia.SJ.50 

7,500 mfd 200 Vdc 

b 3/4" x 3" dia. S4 .00 

12,000 mfd 40 Vdc 

4 1/4" x 2" dia, $2*50 

22,000 mfd 25 VdC 

4 3/4 H x 2" dia. 52.50 

48,000 mfd 10 Vdc 

3" v. 2 1/2" dia. $2.50 

66,000 mfd 15 Vdc 
3 3/4" x 3" dia. S3. 50 

72,000 mfd 15 Vdc 

4" v- 2"' dia* $3.50 

100,000 mfd 10 Vdc 

6" x 2 1/2" dia. si. 00 




S.P.S.T. 



CARLING 
(on-off J 

TOGGLE RATED. 

SWITCH L0 flm P 

§ 125 Vac. 

All plastic body 

and toggle. 

CAT! 5T5- 



$1.00 ea 
10 for$8.50 
100 for $7,50 
LARGE QUANTITIES 





tail light, emergency 
warning light, or 
special^ef f ects lamp. 
Red reflective lens 
is 2 3/4" jc 5 1/2" 
is mounted on a 
4* high pedestal 
with up^down swivel 
ad justment. Includes 
12v replaceable bulb* 
CATt TLB $3.95 each. 



XENON FLASH TUBE 



3/4" long X 1/8" dia- Flash 
tube designed (or use in 
compact camera flash units. 
Ideal lor experimenTcrs. 
CAT* FLT-1 2 lor $1.00 



LED'S 

STANDARD JUMBO 
DIFFUSED T 1-3/4 

RED 10 for $1-50 



MICRO-CASSETTE MECHANISM 

Micro-cassette tape transport for 

standard MC60 or MG45 

micro .casSfitlas. 3 Vdc operation. 

Contains: drive motor, belt, head, 

capstan, pinch wheel and other 

components. 3 1/2" X 2 1/4" X 5,'8 _ 

CAT* MCMEC $3.00 each 10 lor 127.50 





GREEN 
YELLOW 



10D tor 113.00 

10 (or 12.011 

100 lor 117.00 

to lor 12 00 

100 tor 117.00 



I 



FLASHER LED 

5 volt operation 
red jumbo T 114 sue 

GMtlEChl $1.00 
NEW GREEM FLASHER 
CATILSD-tG $1.00 

BIPOLAR 



t 



jumbo Tissue 
2 lor SI 70 



48 KEY ASSEMBLY 
FOR COMPUTER OR 
HOBBYIST 




LED HOLDERS „ 
Two piece holder ^^ rR 
Fw jumbo LEG 
lOforSS* 100 lot 35. (X? 

CLEAR CLIPLITE 
LED HOLDER 

Mane LEDa fancy j 
indicator. Clear. 
4tarfljM 



D.RS.T. LIGHTED 
ROCKEH SWITCH 

IHrrte irotitsti rocker. 

snap mounts in 

it'xiWi hole 
Orange lens 16 amp 
contact 

$1,50 

MINI-PUSHBUTTON 

S-PS.T. momentary 
normally opAn 
%- bushing 35t*Jcn 

Bed tjutton. ^ o to T $3.00 



SNAP ACTION 
SWITCH 



Cherry elect. *E-2i. N.O.mN.C, 
Q.1A contacts. SuttaWe ror alarms 
and other low energy circuits 
11a" lever. 

AStEACH 10 FOfl 14.10 




WALL 

TRANSFORMERS 



all plug dircctsyii 
into 120 vac 

outlet 
4 VDC ■ TO mi. 
VAC Q 500 ma. 
6 VDC a ™ me- 
SVDCrssoOms. 
12.5VAC«S2S5me. 
IB VAC ffl 11 VA and 
4.5 VAC & 1.ZB VA 
24 VAC @ 250 m >. 
MULTI- VOLTAGE tfy 500 
12' 



12 00 
13.50 
14.50 
15.00 

13.00 

«.so 

13.00 



3,4Vl,S,7Vi,(or12VDC 17.50 

TRANSISTORS 



2N70S 

2N2S22A 

PM22S2A 

2N2904 

ZN2905 

MJ2955 

2K3055 

PHD 10K40 

TIP 1J1 

TIP 125 



4lqr$1.00 

3 (or 11.00 

4 tor 11 .00 
3 tor 31.00 
3torii,00 

11.50 

(1.00 

11.00 

75* 

75t 



WE'VE MOVED 

Our Mall Order Operation* 
NEW u> " rv * Ub#t 

MAILING ADDRESS 
P.O. BOX 567 



NEW T.I. KEYBOARDS. OrvjhaHy 
used on computers, these key- 
boards contain 4B S.P.S.T.mech- 
anical switches- Terminates to _ 
1 5 din connector. Frame4 _ x9" 
CATt KP- 48 11.50 ...„ I VAN NUYS, CA 91408 




EDGE 
CONNECTORS 

ALL ARE. 156' SPACING. 

*rfillt tiwitiiimttrtnunii 
12 EDGE CONNECTOR 11.25 •• 
solderlogstyle lOforltl.OO 

22/44 EDGE CONNECTOR 
12.00 H RC.slyla 10 lor 115.00 

22/44 EDGE CONNECTOR 

soloertug style 12.50 each 

21'5S EDGE CONNECTOR 

RC styla 12.50 « 

3«/72 EDGE CONNECTOR 

RC. style 13.00 >lcn 

43/16 EDGE CONNECTOR 

RC.styra H.SOeich 



WALL 

TRANSFORMER 

11.5 Vdc 

\^\ 1-« 
Amp. 

1 ^ r INPUT: 

SIZE: 120 Vac 
3 3/4" X 2 7/8" X 2 5/8" 
CAT t DCTX-11519 

S6.50 ooch 



TRANSFORMERS 



120 volt 

pnmarira 



m 



2K 10 TURN 

MULTI -TURN POT 

SPECTROL 

#MOD534-Tl6l 



iA VOIH & 750 ilia. 
6.3 VQlt it SOD mi. 

13 V.CT. & 200 mi. 
12 «CT, £t 400 rn*. 
12 V.C.T. & 1 «T»p 

11 V.CT. & lamp 

12 VrC-T. %% * *mf\ 
11 will ffl 660 mi. 

14 V£-T. © 100 ma. 
24 V.CT. o i amp 
24 V.CT ft 2 imp 
24 V.CT. ® 3 imp 
24 V.CT. O 4 amp 



J3.00 

II. 75 

12.00 
13/00 
(*.OD 
S4.B5 
4700 
S2 .00 
S2.50 
J4B5 
S6.7S 

(11.00 



RELAYS 

10AMPSOUDSTATE 

lONTROL^-JSv^c r®J*\ 

LOAD: 140 vac 10 amp 1 , V € -^r?- 

jIZEj 2MT il-il 1 iiiXj 
19.50 EACH 10-FOR *90.00 

ULTRA-MINIATURE 

5 VDC RELAY 

Fujitsu 9 

FBR£1tNEO0O5M20 
Htan sensitivrty 
COIL: 120onm5 
CONTACTS: lamp 
Mountain 14 pin DIP socket 
H.25»Kti 10torI10.MI 

MINIATURE 

6 VDC RELAY 
Aromat #RSO-6V 
Super Small 
S.RD.T relay 
GOIdcolDali 
contacts rated 

1amp@30vdc Highly sensitive, 
TTL *act dtiva possibw 1 20 ohm 
coll. 

Oparale Irwti 4.3-6 vdc 
COIL: IZDffin-,5 S1.5BHCH 

l'/n ""/«'" 7.|' 10 lor 11 3.50 

13 VDC RELAY 

CONTACTS: SRN.C 
10anq>@12rjyac 

Energizocoilto 
open contact . . . 
COIL" 13 vdc 650 ohms 

S PE C1AL PBIC E 5 1 . 00 n a c h 

4PDT RELAY 

14 pin KH style... 
3 amp Kmtacts . 
USED Put tuny 
tostad . , ,1.1.70 each 
spGiiry exja voltage desired 
Eathef 24 vdc or 120 vac 
LARGE QUANTITIES AVAILABLE 

SOCKETS FOR KH R ELAT 
75c tach 



Tl SWITCHING POWER SUPPLY 



Compact., wflJI-rt^kJljiEecl switching powef supply 
designed ic^ power lexas lnal^mErnisoofTipy!«?f 

INPUT: M - 25 vac ®1 amp ■ >rt L IiRL 
OUTPUT *l?vdc@350ma. PRICE 

* 5 vdc @ I 2 amp 



- 5 vdc @ £00 

SIZE ^^'xi'.i' Rl'ii-lT™ 



sr 



% 3 50 




13.8 VDC REGULATED POWER SUPPLY 



Trifl&G are sotid ata(o. fully ■■oflLrlaiad 13.& vdc 
power supplies. Bom Feature 1 &&*<> solid stele 
■ccwisUuclJon, (use protection, and L E.D.poww 
Indtcaior. u. L listed 

2 ampionatont, 4 nmpiLirgn $20.00 each 

3 emp eomtnit.. S amp turg* $27^0 *ach 




TELEPHONE JEl 
COUPLING %& 
TRANSFORMER 

Stincor t TTPC4I 
SOOchmf c.l. 1o BOO rjhmi c.l 

P.C. board mount 

W"it5fl"n3W" 



SOUND AND VIDEO 
MODULATOR 

TI#Urtl3&l-l Designed for use with 
T.I- computers. Can o-e used with 
video cameras, gaffies or other 
audio/video sources. Built in A/fl 
switch enables user to switch from 
T.V. antenna without disconnection 
Channel 3 or * seletion. Operates on 
12 Vdc. Hook-up diagram included. 
CAT* AVMOD S5.00 each 




RECHARGEABLE 
NI-CAD BATTERIES 



AAA SIZE 1. 25V $1 3 5 

AA SIZE 1.25V SOOmAH $1.85 

AA ,m: :,-: :.::■ $2.00 

C SIZE 1.2V l.'ji.:niAr S3. 50 
SUB-C SIZE soldeMati $3.50 
SIZE ] 2V 120rjmAH $3.50 



NI-CAD 

CHARGER 

TESTER 



Will charge 
most every 
size 
Hi-cad 

battery 
available 




Cat! UHCC-H S12.50 



8" 15 WATT SPEAKER 

C.T.S Model SB3079 ^£ 

Full range speaker. tVyp^S 
100-io.tsooHi: **(C\W 

Ideal Tor PA syat&rm. (t-^ffj 
Mounting lutes for 
line-matching tranilormei. 

CATaSKJUS 
13.50 *a. Cast of B pea. 
125.00 par case 




LJ 

g 

Q 
< 
LC 

98 



STORES 
LOS ANGELES, CA 
905 S. Vermont A VI. 
213 360-8000 
VAN NUYS. CA 
$228 Sepulveda Blvd. 
SIB 397-1 80S 



MAIL ORDERS TO: 

ALL ELECTRONICS 

P.O. BOX 587 

91408 
TWX- 101010163 
ALL ELECTRONIC 



QUANTITIES LIMITED 

minimum ortoERE sio ci, TOLL FREE ORDERS 

CALIF. ABO SALES TAX 800-826-5432 

USA: S3.D0 SHIPPING 

NOC.O.D.I 

FOREIGN ORDERS: 

INCLUDE SUFFICIENT 

SHIPPING. 



INFO • (213) 380-8000 
FAX - (213) 389-7073 



POLARITY SWITCH 



external coaxial relay on a v 
satellite TV system. IDEAL FOrVI^ 553 
THE EXPERIMENTOR AS PARTS,?; 
Heavy chassis box containing a **™ 
CA 358 op ampl 
and other parts. Catalog I rdfs 
SI. 7 5 each 10 for S15.0Q 




SOLID 
STATE 

BUZZER 

Star #SMB-OBL 

6 vdc 

TTL compatiWa. 

Sl.&Dfl&ch 
10 lor $9.00 



CIHCLE 107 ON FREE INFORMATION CARD 



that's New at 

AMERICAN DESIGN COMPONENTS? 



"The Source" of the 
electro-mechanical components 
for the hobbyist. 



We warehouse 60,000 
items at American 
Design Components — ex- 
pensive, often hard-to-find 
components for sale at a 
fraction of their original cost! 
You'll find every part you 
need — either brand new, 
or removed from equipment 
(RFE} in excellent condition. 
But quantities are limited. 
Order from this ad, or visit 
our retail showroom and find 
exactly what you need from 
the thousands of items on 
display. 

OpenMon. - Sat., 9-5 



THERE'S NO RISK. 

With our full 90-day warranty, 
any purchase can be returned for 
any reason for full credit or refund. 



ADAM COMPUTER. 

5 X A" 

DISK 

DRIVE 




Gives your Adam fast, reliable data 
storage and retrieval. Can hold up to 
16GK bytes of information. Uses industry- 
standard SS/DD disks. Connects directly 
to your Adam memory console. Comes 
with disk drive power supply* Disk 
Manager disk and owner's manual, 
Mfr - Coleco, Model 7817 
Item #12630 $199.00 New 



ADAM Accessories. . . 

ADAM COMPUTER KIT - 

(Less printer.! Includes: Keyboard, digital 
data drive. 2 game controllers, power sup- 
piy, all memory boards* and one cassette. 
No wiring necessary; hook-up diagram incl. 
Hem #7410 $99,00 

COLECOVISION to ADAM 
EXPANSION KIT - 

Plugs into your Colnco Vision. With printer 
power supply & one data drive, you'll have & 
working Adam Computer! Keyboard & one 
Smart Basic cassette also included. 

Item #3318 $59.50 
ADAM PRINTER - 

Item #BB39 $69.50 

DATA DRIVE - 

Item *6B41 . 
LASTCHANCE- $19.95 

PRINTER POWER SUPPLY - 

Item #6642 $14.95 
ASCII KEYBOARD - 

Item #6643 $19.95 

CONTROLLERS - 

ISetof4) ltem#70T3 $9.95 

ADAM CASSETTES - 

(Consisting of Smart Basic, Buck Rogers 
fit blank cassette.) 

ltem#77BB jij -. - 
BAKERS DOZEN - $19.95 

LOGIC BOARD- 

tPartsonly.l ltem#7231 $9.95 

GAME BOARD- 

IPartsonly.l Item #7679 $6.95 

ADAM LINK MODEM - 

(Software included.) 

Item #12363 $29.95 

AUTO -DIALER 

ADDRESS BOOK - . „ „ 

Item #12365 $19.95 



PC 8300 

HOME COMPUTER 

(Advanced version 
of the Umax 1000] 




42-key mechanical keyboard I not 
membrane). Contains 2K of 
RAM. Reverse video. 2 BOA, 
6.5MHi processor, ROM 8K 
BASIC. Graphics capability/sound- 
music, TV or monitor. Joystick 
input operates on 115 VAC. In- 
cludes: AC adapter, TV cable, 
and pair of cassette cables. Will 
run ell prerecorded tapes for Sin- 
claWTimex 1O0O-ZX81. Mfr - 
Power 3000. In orig. boxes. 
Item #10336 $29.95 New 

Accessories. . . 

* 1 6K RAMPACK upgrade 
Item #10337 $9.95 New 

* 32K RAMPACK upgrade 
Item #12148 $19.95 New 

* COLOR PACK 

Item #12147 $19.95ljew 



12", High Resolution 
TTL MONITOR 




Z%", 10Mb 
HARD DISK DRIVE 
{IBM® Compatible) 




Fits standard S&" spacing. 
Shook mounted. High speed, low 
power. Mfr — Rodime #H0252F 
Item #10151 $159.00 New 

Controller Card for above 
Item #10150 $89.00 




5 1 /i" 

FULL 

HT. 

DISK 

DRIVES 

48TPI 

[IBM' Compat.) 

Double sided /double density, full 
height drive, 48 T.P.I. , 80 tracks. 
Mfr - TandonTM 100-2 
Item #7328 $79.95 

2 for $150.00 

96 TPI, DS/Quad Density 

Mfr - CDC #940ST 

Item #1893 $99.00 



SWITCHING POWER 
SUPPLY 




12 VDC/110 VAC Iw/built-in 
power supply}. Green phosphor. 
Mtd. in metal housing- Schematic 
supplied. Mfr — Ca patron ic 
#05-1030: .„_ _.-_ 

Item #BB11 $19.95 New 



115 & 230V, 47-440 Hz. 
Inputr 9Q-135V7180-270V 
Output: 5VDC@5.5A 
+ 12VDC@.4A 
- 1 2VDC @ ,3A 
Perforated metal case enclosure, 
Dim.:9rt-Lx3>S-Wx2"H. 
Mfr — General Instrument 
Item #79B3 $14-.95Nev 



5%\ 1.2 Mb. AT 
HALF HT. DISK DRIVE 




48/96 TPI 

(IBM"" Compatible) 

Double sided, single/double 
density; 80 track. 
Mfr - Panasonic #JU-475 
Item #10005 $119.00New 



5%" 
1 12 HT 
DISK 
DRIVE 




DOS 3.2 Compatible 

96 TPt, DS/QUAD DENSITY 

Tan don TM55-4 DS/Quad 

Item #1304 $79.00 
2 for $150.00 



COMPUTER GRADE 
POWER SUPPLY 



Other usas-rvns CB & car radios. 
Comas ready to pkig in? 
DC Output: - 5V @ ,5 amp. 
+ 5V @ 3 emp. 
+ 12V @ 6 amp. 
Input 115VS60H. Dim.: 9M "W 
x3#'H. LRubterft-ifKlL) 

Item -9501 $24 95 New 



15" COMPOSITE 
VIDEO . MONITOR 



\ i 



15*, green phosphor, high reso- 
lution [1 2 tines center) and: band- 
width from IOHi to 30Hj ± 3dB. 
Operating volt. : 120/240VAC, 
50/60H1-, 65VA max. 
Mfr — Motorola - Alpha Series 
hem #10044 $34.95 New 



Insides of the 
Commodore Computer 




^! 




. 



Commodore VIC 20 CPU board & 
mechanical keyboard. Guaranteed 
not to work, (For parts only.) 
Item #12144 $14.95 RFE 



Hl-POWER 
SWITCHING 
POWER SUPPLY 




Output; *5,15V@>70A 

+ 1 2V ® 4A 

+ 1 2V fi> 4A 
+ 5.2V@5A 
Input: 11 5/ 2 30V nominal, 
.72SKW cont, 47-63HI. En- 
closed in metal housing. 
Dim.: 15"Wi( 2Vi"Hx6" deep. 
Mfr - Todd Prod. #4XS8 1 S 1 A 

Item #9749 $29.95 New 



PUMPS-COMPRESSORS-BLOWERS-MOTORS- POTENTIOMETERS- COUNTERS 
TIMERS -RELAYS -VOLTAGE REGULATORS -POWER SUPPLIES 



1 -PIECE 
TELE- 
PHONE 



Touch- 
tone to 
rotary (may 

be used 
even where 
there is 
only 
a rotary 
phone]. 

Features: I a si number radial & 

mute button. Comes w/15" cord 

& standard modular plug. 

Color: Ivory, Mfr — Spectra -phone. 

Modal OP-1. Item #10748 

$6.95: 3 for $15.00 New 



JOYSTICK 
CONTROLLERS 




Fits Atari, Apple, Commodore. 
and our #10336 PC8300 Com- 
puter. Has 4-ft. cord with plug. 
Dim.: 3)4" sq. xl ft" H. 
Item *12143 $5.95 New 



12/24VDC 

MUFFIN- 
TYPE 
FANS 



V'V 



55/100 CFM 

S W. Can be mounted lor blow- 
ing or exhaust- Aluminum hous- 
ing, ptushless, ball-bearing type. 
1 " Thin: 5 plastic blades with 
feathered edges. 
Mfr - Centaur KCUDC24K4 601 

ltam#B541 $19.95 New 
1 Vj" Standard: 5 plastic blades 
Mfr - Centaur #CNDC24K4-601 

Item *1 21 03 $14.95 RFE 



AT-STYLE 

COMPUTER 
CABINET 



Contains 1 tulMength expan- 
sion slots (w 'guide si. With room 
for an internal 5 V* " hard disk 
drive. Has 3 half-height disk drive 
slots. Rear on/off switch, notched 
to hold in power supply I not 
incl.h and security switch w/key. 
Item #12266 $49.95 New 



AMERICAN DESIGN COMPONENTS, 62 JOSEPH STREET, M00NACH1E, N.J. 07074 



YES3 Please send me the following items: 
How 
Many? Description Price 



Item 
No. 





















































Total 




Shipping & handling, we ship UPS unless 
r"-~^_^ otherwise specified. Add $3 plus 10% total. 
/ ^c"^~~~-~^ Canadian: S3 plus P.O. cost. Charge only. 

/ C 4Tai n^8?~~~ > SalES Ta * (N - J - ™siaents only. 
4*W) gl u G s 9n / please add 6% of total) 

^^23^0ro< B ; / ORDER TOTAL 






1 



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ORDER 

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J AH inquiries end f/ee catalog requests Cat/ 201-939-27W. 



For all phone orders, ca// TOLL- FREE 800-524-0809. In New Jersey, 201-939-2710. 



> 

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99 



CIRCLE 195 ON FREE INFORMATION CARD 



THIS 45 SQ. INCH t^PB 
LIGHT PANEL IS .035 
INCH THICK PRODUCES 
NO HEAT COMES IN 3 
BOLD COLORS HAS ITS 
OWN 12 VOLT POWER 
SUPPLY ANDTHATS 
WHY WE CALL IT, 



iTS4 ' 



They were developed by the computer industry 
a: hi- tec LCD. back lights you can bend and Lwist 
them into almost any shape, Tbe white one turns 
a brillant coiboll blue, The pink one turns bright 
while, The green one, veil it looks like the power 
source from a space ship! A manual explains how 
they work and the assembly directions are clear. 
Even the solder is included! 

EACH 139 KIT INCLUDES: 
1 INSTRUCTION MANUAL WITH THEORY SECTION 

SEND !5 (APPLIED 70 PURCHASE) FOR THE MANUAL ON LI 

5:L1GHT PANELS: 

1EA 10 INCH BY -j.5 INCH (SPECIFY WHITE 0! BLUE) 

1EA 9.3 INCH BY 2.5 INCH (pink that turns white) 

3EA 9.5 INCH BY 2.5 INCH [MELT DOWN GREEN) 
I:POWESSUPPLYKIT 

15 DHY mOIlEY BflCK THIHL 



Call for a copy of t S do* trial agreement. Tax & 
rrenht extr».5end check pr arid 1.90 far COD. 
Price mes change Store Price mt* differ. While 
supplies leat. Ho POe* terms > or credit ctrdj 



S iliconValle y S urplus 

415-261-4506 

4401 OAK PORT OAKLAND CA, 94601 



OPEN 

1 0am- 6pm 

CLOSED 

5UN&M0N 



CALL OUR BBS 415-261-4513 
CIRCLE 186 ON FREE INFORMATION CARD 





miM 


d 




SCIENTIFIC & ELECTRONIC 
PRODUCTS 




PLANS— Guild YourseSF— All Puts AvailaMe In Stock 

• LC7— BUflNING CUTTING COa LASf R S 20.00 




■ RUM-POKTABLE LASER RAY PISTOL „ 20.00 




• TCC1— 3SEPABATETESLA00IL 

PUNS TO 1.5 MEV 20.00 




• IOG1-I0N FUVGUN 10.00 




• GRA1 —GRAVITY GENEflATOFt 10.00 




« fMLI-ELECTRO MAGNET COtL GUNJUUHC 

KITS 

• MFT1 K-FM VOICE TRANSMITTER 3 Ml RANC 

■ VWPM5K-TELEPH0NE TRANSMITTER 3 Ml 

• 6IC3K-250.00 VOLI 10-H" SPARK TESIA 

• LHC2K- SIMULATED MULTICOLOR LASER.. 

■ BLS1K-1 00,000 WAn BLASTER DEFENSE [ 
'ITM1K-10O.O0O VOLT 20' AFFECTIVE 

RANGE INTIMIDAT0R 


HER 6.00 




E 49.50 

WNGE 39.50 

MIL 199.50 




39.50 

PACE 69.50 

B9.50 




• PSP4K— TIME VARIANT SHOCK WAVE PIST0. 

• RTG1K-SPECTACULAR PLASMA 
TORNADO GENERATOR 


59.50 




149.50 




• MVPIK SEE IN DARK KIT 




ASSEMBLED 

• PG7OH-MULTICOL0RE0 VARIABLE 
MODE PLASMA GLOBE "7" 

• BTC10-50.000 VOLT-WORLD'S SMALLES 
TESLACOIL 


425.00 

44.50 




• LGU40-1MW HeNe VISIBLE RED LASER GU 

• TAT2D AOT0 TELEPHONE RECORDING 0EVIC 

• GPV10-SEE IN T0TAI DARKNESS IR VI EWE 
« UST10-SN00PER PHONE INFINITY TRANSt 

• IPS70-INVIS1BLE PAIN FIELD GENERAT0R- 
MULIIMODE 

• CATALOG CONTAINING DESCRIPTI0 

HUNDREDS MORE AVAILABLE FOR $1 . (X 
WITH ALL ABOVE ORDEFtS. 
PLEASE INCLJDE S3. 00 PH ON ALL K 
PLANS ARE POSTAGE PAID. SEND CHE 
OS F0NDS. 

INFORMATION UrJ 

P.0.B0X716DEPT.RE.AMH 


1 299.50 




E 24.50 




1 299.50 


co 
o 

z 

1 

ts 

HI 

_l 

LU 

6 

Q 
< 

or 


mEfi 169.50 
M.W 

js of above plus 
or include free 

is and products 
;k,mo,visa,mcin 

LIMITED 

IRST, NH 03031 



ADVERTISING INDEX 



RADIO-ELECTRONICS does not assume any responsibility for errors that may appear 
in the index below. 



Free Information Number 



Page 



81 A.I.S. Satellite 79 

108 AMC Sales 29 

107 All Electronics 98 

103 Allen W.O .....38 

— Amazing Devices , 100 

195 American Design Components 99 

98 Beckman Industrial . 3 

85 Blue Star Industries 78 

109 C&'S Safes 14 

— C.O.M.B 16 

60 CIE 34 

89 Cameo Enterprises 79~~ 

54 Chemlronics 33 

196, 19S Circuit Cellar 78, 79 

— Command Productions . . 29 

203 Computer Technologies ............. 72 

194 Cook's Institute 24 

193 Crystek 8 

200 Dactron , 12 

127 Dsco Industries 78, 79 

189, 190 Dick Smith Electronics 90 

82 Digi-Key 87 

— Electronic Technology Today . 78, 79 CV3 

120 Elephant Electronics 24 

111 Elronix 81 

10O Firestik II 29 

188 First Street Computer 26 

— Fordham Radio 10 

— Grantham College of Engineering 5 

86, 176 Heath 9. 20 

— ICS 8t 

65 J& W IS 

59 JDR Instruments 7 

1 13, 182 JDR Microdevices 92, 93 

183, 184 JDR Microdevices 94, 95 

185 JDR Microdevices 96 

114 Jameco 88, 89 

104 Jan Crystals 33 

87 MCM Electronics 91 

204 MD Electronics 79 

93 Mark V. Electronics 85 

205 Mercer 13 

61 Microprocessors LTnltd 72 

— NRI 11, 17 

187 NTS 79 

— Ncsda 28 

202 NuScopc Associates. . , 72 



191 OCTE Electronics 79 

110 Omnitron 31 

— Pacific Cable 83 

181 Parts Express 84 

101 Pomona Electronics CV4 

78 Radio Shack 97 

177, 178 Sencore 21, 23 

179, 180 Sencore 25, 27 

186 Silicon Valley Surplus 100 

74 Solid State Sales 86 

94 Star Circuits 79 

92 Tektronix CV2 

66 W.S.Jenks . . . ... ..... ... 26 



Gernsback Publications, Inc. 
500 B Bi- County Blvd. 
Farmingdale, NY 11735 
(516) 293-3000 
President: Larry Stockier 
Vice President: Cathy Steckler 

For Advertising ONLY 

516-293-3000 
Larry Steckler 

publisher 
Arline Fish man 

advertising director 
Shelli Weinman 

advertising associate 
Lisa Strassman 

credit manager 
Christina Estrada 

advertising assistant 

SALES OFFICES 

EAST/SOUTHEAST 
Stanley Levi tan 

Eastern Sales Manager 
Radio- Electronics 
259-23 57th Avenue 
Little Neck, MY 11362 
718-428-6037, 516-293-3000 

MIDWEST/Texas/Arkansas/ 

Okla. 

Ralph Bergen 

Midwest Sales Manager 

Radio-Electronics 

540 Frontage Road — Suite 339 

Northfield, IL 60093 

312-446-1444 

PACIFIC COAST/ Mountain 

States 

Marvin Green 

Pacific Sales Manager 

Radio-Electronics 

15335 Morrison St.— Suite 227 

Sherman Oaks, CA 91403 

818-985-2001 



100 



Electronics Paperback Books 

EVERY BOOK IN THIS AD $6 OR LESS! 






m 



M 



^ 




n BP12S— 25 SIMPLE AMATEUR BAND ANTENNAS 55.00. All are inexpensive 

to build, yel perform well. Diodes, beams, triangle and evert 3 mini rhombic. 

D BP12B-^0 PROGRAMS FOR THE ZX SPECTRUM AND 16K ZX8Z SS.7S. 

Included wilh each program is a flow charl and a description ol what happens. 
Notes for converting programs lor use on other computers are also included. 

□ 160— COIL DESIGN i CONSTRUCTION MANUAL., ...55.95. How the hobbyisl 
can build RF. IF, audio and power coils, chokes and transformers. Covers AM, FM 

and TV applications. 

D JOB— PRACTICAL STEREO t QUADROPHONT HANDBOOK $3.00. A refer- 
ence book lor all interested in stereo and multichannel sound reproduction. 

HI BP99— MINI-MATRIX BOARD PROJECTS S5.00. Hsre are 20 useful circuits 

thai can be buift on a mini-matrix board that is jusl 24 holes by ten copper-foil strips. 

n BP157— HOW TO WRITE ZX SPECTRUM AND SPECTRUM r GAMES PRO- 
GRAMS $5.95- A cryslal-clear step-by-slep guide 10 wriling your own graphics 

games programs. 

n BP117— PR ACT1CAL ELECTRONIC BUILDING BLOCKS— Book 1 $5.75, 

Oscillators. Timers, Noise Generators, Rectiliers, Comparators, Triggers and more. 

D 2t9— SOLID-STATE NOVELTY PROJECTS S4.95. Fun projects include Ihe 

Optomin. a musical inslrument lhat is played by reflecting a light beam wilh your 
hand, and many more. 

□ BPt79— ELECTRONIC CIRCUITS FOR THE COMPUTER CONTROL OF 

ROBOTS S5.00. Data and circuits for interfcing the computer to the robot's 

motors and sensors. 

□ BP126— BASIC & PASCAL IN PARALLEL 54.95. Takes Ihese two program- 
ming languages and develops programs in both languages slmullaneously. 

n 224—50 CMOS IC PROJECTS 55.25. Includes sections on mullivibrators. 

amplifiers and oscillators, trigger devices, and special devices. 

[~l 225— A PRACTICAL INTRODUCTION TO DIGITAL IC'S 54.95. Mainly con- 
cerned with TTL devices. Includes several simple projects plus a logic circuit lest 
set and a digital counter timer. 

□ BP170— I NTROD UCTtON TO COMPUTER PE Rl P H E RALS $5.95. Shows tow 

to use a variety of co computer add-ons in as non-technical a way as possible. 

□ 227— BEGINNERS GUIDE TO BUILDING ELECTRONIC PROJECTS 55.00. 

How 10 lackle the praclical side of electronics so you can successfully build 
eleclronic projects. 

[7i BP168— HOW TO GET YOUR COMPUTER PROGRAMS RUNNING 55.95. 

Shows how to identify error in program and what to do about them. 

□ 123— FIRST BOOK OF PRACTICAL ELECTRONIC PROJECTS $3.75. Proj- 
ects include audio distortion meter, super FET receiver, guilar amplifier, rnel ronome 
and more. 

H BP24—52 PROJECTS USING tC 741 55.25. Lots of projecls buill around Ihis 

one available IC. 

O BP110— HOW TO GET YOUR ELECTRONIC PROJECTS WORKING $5.00. 

How lo find and solve Ihe common problems lhat can occur when building projects. 




^*w»» 



**■ 




Hmeirvrr* Tkn«> 




ritoti 



□ BP33— ELECTRONIC CALCULATOR USERS HANDBOOK $5.75. Invaluable 

book For all calculator owners. Tells how to get the most qui of your calculator. 

D BP36— 50 CIRCUITS USING GERMANIUM, SILICON & ZENER DI- 
ODES S5.0D, A collection ol useful circuits you'll want in your library, 

D BP37— 50 PROJECTS USING RELAYS, SCRS & TRIACS 55.00. Build pri- 
ority indicators, light modulators, warning devices, light dimmers and more. 

D BP183—AN INTRODUCTION TO CP/M S5.75. To run and use programs oper- 
ating under the CP/M operating system you will find this book extremely useful. 

□ BP42— SIMPLE LED CIRCUITS S5.00. A large selection of simple applications 

for Ihis simple electronic component. 



U BP127— HOW TO DESIGN ELECTRONIC PROJECTS $5.75. Helps Ihe reade* 

to put projects together from standard circuit blocks with a minimum of trial and 
error. 

I~l SP122— AUDIO AMPLIFIER CONSTRUCTION $5.75. Conslruclion delails for 

preamps and power ampliliers up through a 10D-waH DC-coupled FED amplifier. 

D BP92—CRVSTAL SET CONSTRUCTION $5.00. Everything you need lo know 

about building crystal radio receivers. 

O BP4S—PROJECTS IN OPTOELECTRONICS SS.DO, Includes infra-red detec^ 

tors, transmitters, modulated tight transmission and photographic applications. 

n BPia— ELECTRONIC PROJECTS FOR BEGINNERS $5.00. A wide range ol 

easily completed projects lor the beginner. Includes some no-soldering projects. 

H BP49— POPULAR ELECTRONIC PROJECTS $5.50, Radio, audio, household 

and lest equipment projecls are all included. 

□ BP51— ELECTRONIC MUSIC AND CREATIVE TAPE RECORDING $5.50. 

Shows how you can make eleclronic music al home with Ihe simplest and mosi 
inexpensive equipment, 

\J SPSS— ELECTRONIC SECURITY DEVICES $5.00. Includes both simple and 

more sophisticated burglar alarm circuits using light, infra-red, and ultrasonics. 

n BP59— SECOND BOOK OF CMOS IC PROJECTS S5.00. Moredftuils show- 
ing CMOS applications. Most are of a fairly simple design. 

□ BP72— A MICROPROCESSOR PRIMER $5.00. We starl by designing a smalt 

computer and show how we can overcome its shortcomings. 

□ BP74— ELECTRONIC MUSIC PROJECTS $595. Provides the experimenter 

wilh a variety of practical circuits including a Fuzz Box, Sustain Unit, Reverberation 
Unit, Tremelo Generator and more. 

G BP91— AN INTRODUCTION TO RADIO DXING $5.00. How you can tune in on 

those amaleur and commercial broadcasts from around the world in the comfort ol 

your home. 

C BP94— ELECTRONIC PROJECTS FOR CARS AND BOATS $5.00. Fifteen 

simple projects that you can use with your car or boat. All are designed to operate 

from 12-vol! DC supplies. 




m 




A 




ELECTRONIC TECHNOLOGY TODAY INC. 

PO. Box 240, Massapequa Park, NY 11762-0240 

Name . 

Address 

City 



.Stale . 



.Zip. 



SHIPPING CHARGES IN 
USA S CANADA 
$0.01 to $5 CO 
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S1.00 
S1.75 
$2.75 
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$50.01 and above. $7.00 



™ E " SA s " N " A , Number of books ordered Q 
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Shipping (see chart) £ 

All payments must 
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Tolal Enclosed . S . 



Your Best Source 

for SMD Test Accessories is 

POMONA ELECTRONICS 



PATCH CORD; SMD GRABBER 
BOTH ENDS: MODEL 5301 




SMD TEST TWEEZER" TO BNC 
MALE: MODEL 5142 (SHOWN), 
TO TWO SINGLE STACKING 

BANANA PLUGS: MODEL 5143 




DO-IT-YOURSELF SMD 
GRABBER'": MODEL 5243 



SMD MICROTIP " TEST 
PROBE TO SINGLE 
STACKING BANANA 
PLUG: MODEL 5144 



FREE 1987 GENERAL CATALOG 





PLCC TEST ADAPTORS 
FIVE MODELS: 20 PIN, 28 PIN, 
44 PIN, 52 PIN, 68 PIN 



_LJ__L Pomona Electronics 

1500 E. Ninth St., Pomona, CA 91766 
Tel: (714) 623-3463 




CABLE ASSEMBLY; SMD 
GRABBER " TEST CUPS TO 
BNC MALE: MODEL 5304 



SOIC CLIP" TEST CLIP: MODEL 
5250 (8 PIN); 5251 (14 PIN); 5252 
(16 PIN) SHOWN; 5253 (20 PIN); 
5254 (24 PIN) 



MOLDED BREAKOUT; SMD 
GRABBER - TEST CLIPS TO 
FEMALE BNC: MODEL 5305 






Our Products are available through your favorite/ - 'ectronics parts distributor. 
CIRCLE 101 ON FREE INFORMA .ION CARD